Da Vinci's Unfinished Symphony

Journey into the mind of Leonardo da Vinci, the quintessential Renaissance man. Discover how his boundless curiosity merged art and science, inspiring inventions and masterpieces centuries ahead of their time. This story explores his relentless pursuit of knowledge and the impact of his visionary thinking.

The Anatomy of Water

The old man stood at the edge of the Arno, watching eddies form behind a stone. He was sixty-three, white-bearded, dressed in rose-colored robes that marked him as distinctive even in Florence's sea of eccentrics. But Leonardo da Vinci paid no attention to passersby. His eyes tracked the spirals. Water curled backward on itself, creating vortices that mirrored patterns he'd seen elsewhere—in the curl of hair, the whorl of a shell, the turbulence of blood leaving the heart. He had been standing there for an hour. Maybe two. Time dissolved when he observed. Later, in his studio, he would draw what he'd seen: page after page of spirals annotated in his peculiar mirror script, right to left, as though writing for an audience that lived on the other side of a looking glass. The notes would discuss hydraulics, then pivot without warning to the curl of locks around a woman's face, then back to engineering problems for canal systems. To anyone else, it would seem scattered. To Leonardo, it was the same inquiry. Everything connected. The spiral was a universal grammar, and he was learning to read it. This was 1515, three years before his death, and Leonardo was still trying to finish what he'd started fifty years earlier: a complete understanding of how things worked. All things. The flight of birds. The growth of trees. The movement of clouds. The mechanics of human emotion as it registered on a face. He had dissected more than thirty human corpses, his hands inside the architecture of mortality, mapping every muscle and tendon. He had designed weapons that could rain death from the sky and painted faces so lifelike that observers swore they could see breath. He had engineered impossible bridges, diving suits, helicopters centuries before the technology existed to build them. And still he felt he was only beginning. His notebooks—thousands upon thousands of pages—were a cathedral of curiosity that would never be completed. They contained drawings of machines that wouldn't be built for four hundred years. Observations about the nature of light and shadow that anticipated physics textbooks. Studies of human anatomy that surpassed anything his contemporaries produced. And between these achievements: half-finished paintings, abandoned sculptures, treatises on subjects ranging from the flight of birds to the nature of the moon's glow, all left incomplete. The world called him genius. He called himself a student. But this wasn't modesty. Leonardo genuinely believed he was always on the threshold of understanding, never across it. Every answer spawned new questions. Every solution revealed deeper mysteries. The more he learned about the mechanics of bird flight, the more he understood about air currents. The more he understood about air currents, the more questions he had about water. The more he studied water, the more he saw its patterns repeated in hair, in blood, in the growth of plants. The chain never ended. Knowledge wasn't a destination; it was a deepening spiral, like the eddies in the Arno. His contemporaries found this exhausting. His patrons found it infuriating. He had a reputation for never finishing what he started, for accepting commissions and then vanishing into tangents. He'd spend months designing the staging for a pageant, inventing mechanical lions that walked and opened their chests to reveal lilies. Meanwhile, the altarpiece he'd been commissioned to paint gathered dust. He'd become obsessed with the mathematics of perspective, spending weeks calculating vanishing points, while a fresco crumbled because he'd experimented with an untested technique for applying paint. Yet when Leonardo did complete something—truly complete it—the result shook the world. The Last Supper stopped people in their tracks. The Mona Lisa became the most famous face in history. His drawings of the Vitruvian Man—the human figure inscribed in circle and square—became the defining image of Renaissance humanism. These weren't just artistic achievements. They were investigations. Each painting was research. Each sketch was a hypothesis tested. This was what made Leonardo different from other artists, other inventors, other scientists of his age. He recognized no boundaries between disciplines because he understood they were all the same discipline: the study of nature's deep structure. Art and science weren't separate pursuits. They were different languages for describing the same reality. To paint a face accurately, you needed to understand the muscles beneath the skin. To design a flying machine, you needed to observe how birds distributed their weight. To capture the play of light on fabric, you needed to understand optics. Leonardo didn't merely paint what he saw. He painted what he understood. And his understanding ran deeper than the surface of things, down into the mechanics, the mathematics, the invisible forces that made the visible world possible. Which is why, perhaps, so much remained unfinished. Understanding had no end point. There was always another layer, another connection, another spiral within the spiral. The world was infinite in its complexity, and Leonardo couldn't stop looking. That April afternoon by the Arno, watching water fold over stone, he was doing what he'd always done: reading the book of nature, taking notes, trying to see past the surface to the grammar underneath. The eddies formed and dissolved. Light scattered across moving water. The patterns repeated. And Leonardo, student of everything, stood witness to the machinery of existence, sketching it out for an audience that wouldn't arrive for centuries.

The Anatomy of Water

The Bastard of Vinci

He was born illegitimate in 1452, in a stone farmhouse overlooking the town of Vinci, twenty miles west of Florence. His father, Ser Piero, was a notary—respectable, upwardly mobile, destined for success in Florence's bureaucratic machinery. His mother, Caterina, was a peasant girl, possibly a slave from the Middle East. The liaison produced a son, but not a marriage. Ser Piero married someone appropriate within a year. Leonardo was raised in his grandfather's house, part of the family but separate from it, legitimate enough to bear the family name but barred from following his father into the notary profession. This outsider status shaped everything that followed. Had Leonardo been legitimate, he would have received the classical education typical of his father's class: Latin, Greek, rhetoric, the traditional curriculum designed to produce lawyers and civil servants. Instead, he received a basic education in reading, writing, and mathematics—vernacular Italian, not Latin—and was left largely to his own devices. While his legitimate half-siblings (Ser Piero would eventually father eleven more children) were drilled in Cicero, Leonardo roamed the Tuscan hills, watching water flow in streams, observing how birds adjusted their wings, studying the way light filtered through leaves. It was the best education he could have received for what he would become. Because Leonardo didn't learn to think inside the boxes that formal education constructed. He wasn't trained in the Aristotelian physics that university scholars accepted as gospel. He didn't inherit the assumptions about what art could be, what science should investigate, which questions were worth asking. He learned by looking. By testing. By refusing to accept explanations that didn't match observation. Later, he would write with something approaching pride: "Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy—on experience, the mistress of their Masters." This was radical. In the fifteenth century, knowledge flowed from authority. You learned what Aristotle said about motion, what Galen said about anatomy, what Ptolemy said about astronomy. You didn't question; you commented. Scholarship meant reconciling ancient texts, not conducting experiments. But Leonardo, lacking the classical education that would have taught him to revere these authorities, simply ignored them. If Aristotle's physics didn't explain why stones fell, then Aristotle was wrong. Leonardo would find out for himself. At fourteen, his father recognized that the boy had talent and apprenticed him to Andrea del Verrocchio, one of Florence's leading artists. The workshop was more factory than atelier: Verrocchio produced altarpieces, sculptures, ceremonial armor, stage designs, decorative metalwork, whatever clients wanted. Apprentices learned everything—how to grind pigments, cast bronze, understand perspective, design hydraulic systems for pageants. It was intensely practical. Art wasn't self-expression; it was problem-solving. How do you make metal look like fabric in sculpture? How do you create the illusion of distance on a flat surface? How do you engineer a mechanical device that will astonish an audience? Leonardo flourished. His talent was obvious, almost unsettling. There's a story—probably true—that when Verrocchio was painting The Baptism of Christ around 1475, he had young Leonardo paint one of the angels. The angel Leonardo produced was so superior to everything else in the painting that Verrocchio supposedly put down his brushes and never painted again. Look at that angel now, in the Uffizi Gallery. It's luminous where the rest of the painting is merely competent. The face has a softness, an inner light, that the other figures lack. You can see the future in it—the technique Leonardo would spend his life perfecting, building up thin layers of oil paint and glaze to create the illusion not just of skin but of light passing through skin, of blood beneath the surface, of a living presence rather than a rendered face. But even then, even as a young man producing work that astonished his master, Leonardo was asking different questions than other artists. He wasn't content to learn the rules of perspective; he wanted to understand the optics of human vision. He didn't just paint muscles; he needed to know how they attached, how they moved, what structure lay beneath. He filled notebooks with observations: how water splashed, how smoke rose, how drapery fell. He wasn't merely collecting techniques. He was constructing a unified theory of representation, grounded in an understanding of nature's mechanisms. Florence in the 1470s was the perfect incubator for this kind of ambition. Under Lorenzo de' Medici—Lorenzo the Magnificent—the city had become Europe's intellectual capital. Neoplatonist philosophers debated at the Platonic Academy. Poets and humanists gathered in gardens to discuss ancient texts newly recovered from Byzantium. Architects studied Roman ruins to rediscover classical principles. The air buzzed with the idea that human beings could understand the world, could recover ancient knowledge and surpass it, could place humanity at the center of a comprehensible cosmos. Leonardo absorbed all of it, but he transformed it. Renaissance humanism celebrated human dignity and potential, placing man at the center of creation. Leonardo took this further. He made curiosity itself a form of devotion. To study nature was to study the divine intelligence that created it. Every dissection was an act of reverence. Every observation was prayer. He was also, by all accounts, remarkably beautiful. Tall, strong, graceful, with long curly hair and a beard that drew comparisons to classical statues. He dressed flamboyantly in those rose-colored robes, in an age when most men wore darker colors. He was a vegetarian, unusual enough that people commented on it. He bought caged birds in the market just to set them free. He kept a chaotic household of assistants, students, and companions, some of whom may have been lovers—in 1476, he was anonymously accused of sodomy with a seventeen-year-old model, though the charges were dismissed. Everything about Leonardo suggested someone existing outside normal categories, unbound by convention. The illegitimate son who became the favorite of dukes and kings. The artist who was also an engineer. The man who loved beauty and designed instruments of war. The vegetarian who dissected corpses. The student who surpassed all teachers. By his late twenties, Leonardo had his own workshop in Florence. Commissions arrived. His reputation grew. He painted the Annunciation, the Madonna of the Carnation, worked on portraits and altarpieces. But even then, the pattern emerged. Projects went unfinished. He accepted a commission to paint an altarpiece for the monks of San Donato a Scopeto—the Adoration of the Magi—and worked on it obsessively for months, producing preparatory drawings that showed a depth of composition unprecedented in Italian painting. Then he stopped. Left it unfinished. Moved on. He was thirty when he decided to leave Florence entirely. In 1482, he wrote to Ludovico Sforza, the Duke of Milan, essentially a job application. The letter is extraordinary. Leonardo lists all the things he can do: design portable bridges for armies, create covered vehicles safe from enemy fire, construct catapults and bombards, engineer tunnels and secret passages, build ships that can withstand cannon fire. Almost as an afterthought, he mentions: "Also I can do in painting whatever may be done, as well as any other, be he who he may." He wasn't being arrogant. He was being accurate. And he was looking for something Florence couldn't give him—freedom to pursue every question that fascinated him, patron who would support not just art but investigation itself. Ludovico Sforza said yes. Leonardo packed his belongings and his notebooks and rode north to Milan, where he would spend the next seventeen years and produce some of the most extraordinary work in human history. The bastard from Vinci had found his stage.

A Thousand Questions Deep

Leonardo's notebooks are chaos and cosmos simultaneously. Open any page and you might find: a sketch of a hydraulic pump beside a study of a child's face, geometrical calculations about squaring the circle next to recipes for paint varnish, detailed drawings of fortress fortifications alongside observations about the nature of moonlight. His handwriting runs right to left, requiring a mirror to read comfortably, cramming every margin with addenda and corrections. The pages feel alive, restless, as though his hand could barely keep pace with his mind. More than 7,200 pages survive. Scholars estimate this represents perhaps a quarter of what Leonardo actually produced. The rest—lost, stolen, scattered, destroyed—exists only as absence, making what remains both precious and fragmentary, like trying to reconstruct a symphony from scattered measures. What makes the notebooks extraordinary isn't just their breadth but their method. Leonardo approached everything—art, engineering, anatomy, botany, geology, hydraulics—with the same technique: observation, question, hypothesis, test. He was doing science before the scientific method had been formalized. Consider how he studied bird flight. He didn't start with theory. He watched birds. For hours. Days. Seasons. He documented how different species adjusted their wings in response to wind. How they banked into turns. How they used their tails for stability. He measured the relationship between wing surface and body weight. He noted which birds could hover, which needed running starts, which soared on thermals without flapping. Then he asked: why? What principles governed flight? He reasoned that air must be a fluid medium, like water. A wing pushing down on air created lift, just as an oar pushing on water propelled a boat. He sketched mechanical wings that could articulate like bird wings. He designed a helix-shaped aerial screw—a proto-helicopter—reasoning that if you could push enough air downward with sufficient force, you could raise weight into the sky. None of his flying machines worked. The technology didn't exist. Materials were too heavy; power sources too weak. But the observations were accurate. The reasoning was sound. He had identified the core principles of aerodynamics centuries before anyone built a working airplane. This pattern repeated across domains. He studied water with the same intensity he studied flight, documenting how currents moved, how waves propagated, how vortices formed. He designed innovative canal systems and flood controls for Milan. He proposed a two-level city plan to improve sanitation and traffic flow. He sketched a parachute—pyramidal canvas stretched over a wooden frame—and calculated that it would allow a person to "throw himself down from any great height without sustaining any injury." In 1485, plague swept through Milan, killing thousands. Leonardo responded by designing an ideal city: streets on multiple levels to separate pedestrian and cart traffic, wide boulevards for air circulation, underground canals for waste removal, standardized buildings with calculated proportions. None of it was built, but the drawings anticipated urban planning principles that wouldn't emerge until the nineteenth century. He approached human anatomy the same way. Dissection was not entirely new—medieval physicians had dissected corpses, though rarely and with religious strictures. But Leonardo dissected differently. He wasn't looking for what ancient texts said should be there. He was discovering what was actually there. He performed dissections at night, usually in hospitals or morgues, working by candlelight, the smell of decay omnipresent. He opened chest cavities and traced blood vessels. He studied the architecture of hands, documenting every tendon. He injected wax into organs to create casts of internal structures. When he dissected a brain, he poured liquid wax into the ventricles to map their shape, then carved away the surrounding tissue—an innovative technique that wouldn't be used again until the nineteenth century. His anatomical drawings are astonishing. The precision exceeds anything produced by his contemporaries. He drew the human heart with such accuracy that modern cardiologists can identify specific anatomical features. He was the first to correctly depict the curvature of the spine. He documented the branching of blood vessels with the detail of a map-maker charting rivers. And he did this while simultaneously theorizing about function: how muscles worked in pairs, how the eye focused, how blood circulated (though he never quite figured out circulation completely—that would wait for William Harvey in 1628). But what truly separated Leonardo from others wasn't just observational skill. It was his insistence on finding universal principles. He noticed that the branching pattern of blood vessels resembled the branching of trees. Trees, in turn, branched like river systems. He measured and found mathematical relationships: the total cross-section of branches at any level equaled the cross-section of the trunk. This held true for blood vessels and for rivers too. It was a universal law, what modern scientists would call fractal geometry. He observed that the sun didn't simply illuminate objects; light bounced between surfaces, colors affecting each other. A red wall would cast reddish light on a white sleeve. A blue sky would tint shadows. This wasn't just useful for painting—it was physics, an understanding of light that anticipated later discoveries. He studied the fossils of marine creatures found in mountains far from any sea. Most scholars explained these as relics from Noah's flood. Leonardo looked closer. The fossils were in multiple layers, separated by rock strata. The shells were mature specimens that couldn't have traveled from the ocean to the mountains in forty days. He proposed an explanation that wouldn't become mainstream for centuries: these mountains had once been seafloor, raised by immense geological forces over vast stretches of time. The Earth wasn't static. It transformed. Everything connected. Art informed science; science informed art. To paint water convincingly, you needed to understand hydrodynamics. To design a functional machine, you needed to understand force and motion. To represent human emotion, you needed to know the muscles that created expression. Knowledge wasn't compartmentalized. It was a web, every strand linked to others. This holistic approach made Leonardo frustrating to patrons who wanted specific deliverables. They'd commission a portrait, and he'd disappear into studies of facial muscles. They'd request a bronze horse, and he'd spend months calculating the metallurgy of casting. He could seem scattered, unreliable, unable to focus. But Leonardo wasn't distracted. He was following connections. Each tangent led to understanding that fed back into the original project. The anatomical studies improved his painting. The engineering work deepened his grasp of materials. The geometric investigations enhanced his architectural designs. It was all one inquiry, deepening spirals of understanding. In Milan, Ludovico Sforza proved remarkably tolerant of this method. Leonardo designed pageants and military fortifications, painted portraits of the duke's mistresses, and worked sporadically on a massive equestrian statue to honor Ludovico's father. The statue would have been the largest bronze casting ever attempted—twenty-four feet tall, requiring seventy tons of bronze. Leonardo spent years on it, creating a full-scale clay model that astonished viewers. But casting technology of the era couldn't handle it. When French armies threatened Milan in 1494, the bronze that was to have been used for the statue was instead cast into cannons. The great horse was never built. The clay model survived until French soldiers used it for target practice in 1499, destroying it completely. Another unfinished project. Another brilliant design that remained in the realm of imagination. Yet Leonardo didn't seem defeated by these failures. If anything, the incomplete projects fed his process. Each investigation opened new questions. Each answer revealed deeper complexity. He wrote in his notebooks: "Just as a large kingdom is made secure by means of small fortified places, so the arts, held together by the union of all their parts, build a strong and lasting reputation." He was building that reputation one observation at a time, one drawing at a time, one question at a time. The notebooks accumulated. The connections multiplied. And occasionally, when circumstances aligned, when a project captured his attention completely, when his technique and vision and the demands of the commission met perfectly—then Leonardo produced something that transcended anything his age had seen. Something that would endure long after the unfinished projects crumbled away.

The Room Where Christ Knows

The refectory of Santa Maria delle Grazie is a long, vaulted room where Dominican monks once gathered for meals. The northern wall is unremarkable. But the southern wall—the southern wall stops time. Twenty-nine feet wide and fifteen feet tall, The Last Supper covers the wall as though the room itself extends into the scene. Christ sits at the center of a long table, the twelve apostles arranged in groups of three on either side. The perspective lines converge on Christ's head, making him the focal point not just of the composition but of the entire space. Windows painted on the wall align with actual windows in the room, creating the illusion that the painted scene occupies the same physical reality as the viewer. But the revolutionary achievement isn't the technical mastery, astonishing as that is. It's the moment Leonardo chose to depict. Every earlier representation of the Last Supper showed a static scene: Christ and the apostles arranged around a table, sometimes with Judas isolated on the opposite side. Compositionally clear. Theologically unambiguous. Safe. Leonardo painted the instant after Christ says, "One of you will betray me." The apostles react. Not uniformly, not symbolically, but as individuals experiencing shock, confusion, disbelief, anger. Their responses cascade outward from Christ in waves of emotion. Some lean toward each other, seeking confirmation. Others pull back in horror. Hands gesture in denial or question. Faces express distinct personalities—Peter's aggressive loyalty, John's grief, Thomas's skepticism, Matthew's earnest inquiry. Leonardo spent months studying faces, sketching people in the streets of Milan, capturing how emotion registered in muscles around eyes and mouth. He understood that grief tightens specific muscles while anger engages others, that fear and surprise share some expressions but diverge in crucial details. The Last Supper isn't twelve generic disciples. It's twelve distinct psychological portraits, each reacting according to temperament and character. Even Judas—especially Judas—is psychologically complex. Earlier depictions made him obvious: isolated, ugly, clutching his money bag. Leonardo placed him among the other apostles, participating in the scene, but recoiling backward into shadow, his face registering guilt and defensive anger. You can read his psychology: he knows what he's done, knows Christ knows, and that knowledge is destroying him. Duke Ludovico Sforza commissioned the work in 1495, intending it as part of a larger project to renovate the church and adjoining monastery. Leonardo began with characteristic thoroughness—hundreds of preparatory sketches, studies of hands and faces, calculations of perspective, experiments with composition. Then he started painting, and the prior of Santa Maria delle Grazie began to panic. Because Leonardo didn't paint the way other muralists worked. The standard technique for wall painting was true fresco: applying pigment to wet plaster, working quickly before the plaster dried, covering a section each day. It was fast, durable, but unforgiving. No revisions. No layering. No time for contemplation. Leonardo hated it. He wanted to work slowly, building up thin layers of paint, adjusting colors, reconsidering details. He wanted the translucent effects he achieved with oil painting. So he invented his own technique: a mixture of tempera and oil applied to dry plaster that he'd treated with a preparatory layer of pitch, mastic, and gesso. It was a disaster, but he didn't know it yet. The technique allowed him to work at his own pace, arriving at dawn some days to add a single brushstroke after staring at the wall for hours, other days painting from sunrise to sunset without pause. The prior complained to the duke that Leonardo was lazy, unreliable, wasting time. The artist would disappear for days, then return and stare at the wall without touching it. Leonardo explained: "Men of genius sometimes accomplish most when they work least, for they are thinking out inventions and forming in their minds the perfect idea." He was solving problems of composition, character, narrative. Each brushstroke mattered. Each face had to be precisely right. Finding the right face for Judas proved particularly challenging. Leonardo sketched criminals and beggars, looking for features that suggested treachery without resorting to caricature. According to the painter's first biographer, Giorgio Vasari, when the prior continued complaining about delays, Leonardo threatened to use the prior's face for Judas. The complaints stopped. For Christ's face, Leonardo wanted the opposite of Judas: not treachery but divine serenity, the knowledge of coming death met with perfect composure. He made hundreds of sketches and never quite satisfied himself. In the end, he left Christ's face slightly indistinct, the features less sharply defined than the apostles', creating an effect of otherworldly calm. The work took three years, from 1495 to 1498. When it was unveiled, the reaction was seismic. People made pilgrimages to see it. Artists studied it, trying to decode Leonardo's techniques. Writers described it in awestruck terms. It became, almost immediately, one of the most famous paintings in the world. But the experimental technique was already failing. Within twenty years, the paint began to flake. By the mid-sixteenth century, substantial damage was visible. Over the centuries, the deterioration continued. Restorers tried to fix it, usually making things worse. Soldiers quartered in the refectory during Napoleon's Italian campaign threw stones at the apostles for target practice. In 1943, Allied bombing destroyed much of the church; the refectory survived, but the vibrations caused more paint to fall. By the late twentieth century, The Last Supper was more restoration than original paint. A massive conservation effort from 1978 to 1999 removed centuries of overpainting and stabilized what remained of Leonardo's work. What visitors see today is fragmentary, faded, a ghost of the original's vibrancy. Yet even in its damaged state, the composition's power is undeniable. Christ's centrality. The apostles' reactions. The moment of betrayal crystallized. Leonardo had created something unprecedented: a narrative painting that captured psychological complexity, a religious scene that felt human, a composition that transformed architectural space. He'd solved problems of perspective, emotion, and storytelling that artists would study for centuries. And he'd done it using a technique that doomed the painting to decay even as he was creating it. It was quintessentially Leonardo: brilliant conception, innovative execution, technical experimentation that didn't quite work, and a final product that, despite its flaws and incompleteness, exceeded anything that came before. He was already looking ahead. While finishing The Last Supper, he was also working on a treatise about painting, designing canals and fortifications, studying geometry, filling notebooks with observations about light and shade. The masterpiece on the wall of Santa Maria delle Grazie was complete, but Leonardo himself never was. There was always another problem to solve, another question to investigate, another mystery to pursue. In Milan, he was celebrated, successful, in the employ of one of Italy's most powerful dukes. He had assistants, commissions, stability. But stability never held Leonardo for long. History was moving, armies were marching, and the comfortable world of Ludovico Sforza's Milan was about to collapse. Leonardo would wander again, carrying his notebooks, chasing questions that had no answers, creating works that the world would treasure and others that would never be finished. The Last Supper would remain on that wall, slowly disintegrating, a testament to both his genius and his restless inability to work within conventional limits. Perfection and ruin, braided together, like everything Leonardo touched.

A Woman Who Watches You Watch Her

French armies invaded Italy in 1499. Ludovico Sforza fled Milan. Leonardo, suddenly without a patron, packed what he could carry—notebooks primarily, always the notebooks—and left the city. He was forty-seven, internationally famous, and essentially homeless. For the next several years he wandered: Venice briefly, then back to Florence, where he hadn't lived in nearly two decades. Florence had changed. The Dominican friar Savonarola had risen and fallen, his bonfire of the vanities consuming artworks deemed sinful before the friar himself was burned in the Piazza della Signoria in 1498. The republic had been restored, but the city felt anxious, less sure of itself than the confident Florence of Lorenzo the Magnificent. Still, it was home, and Leonardo was welcomed. Commissions arrived. The Republic asked him to paint a battle scene in the Palazzo Vecchio, opposite a wall where the young Michelangelo would paint a competing battle scene. It would have been an extraordinary confrontation—the two greatest artists of the age, working in the same room. Neither finished. Leonardo experimented with another new technique involving heated wax-based paint that melted and ran. Michelangelo was called away to Rome. The fragments that survived both projects suggested brilliance, but the walls remain mostly empty. Then, in 1503 or possibly 1504—records differ—a Florentine silk merchant named Francesco del Giocondo commissioned Leonardo to paint a portrait of his wife, Lisa Gherardini. She was about twenty-four, a mother of young children, neither wealthy nor particularly notable. Just a merchant's wife, the kind of person who would normally disappear into history's background noise. Leonardo accepted the commission. And then, for reasons that remain mysterious, he became obsessed. The painting now known as the Mona Lisa is small—thirty inches tall, twenty-one inches wide. Lisa sits in three-quarter view, her body angled slightly away, her face turned toward the viewer, her hands folded at the front. Behind her stretches a landscape of mountains, winding paths, a distant bridge, water that might be river or sea. The background feels dreamlike, not quite real, earth as seen from a great height or imagined from memory. But the face. The face is where Leonardo deployed everything he'd learned about representing human presence. He used a technique called sfumato—"smoky" in Italian—building up countless layers of translucent paint and glaze so thin that individual brushstrokes are invisible. The layers create subtle gradations of light and shadow, avoiding hard edges, making forms emerge from darkness the way objects emerge from mist. Around the eyes and mouth especially, where expressions form, the shadows are delicate, ambiguous. You can't quite pin down what she's feeling. A smile seems to form, then dissolve. Her eyes follow you across the room, but their expression changes depending on angle and light. She seems alive. Not represented but present. Leonardo had been developing sfumato for decades, but in the Mona Lisa he perfected it. He applied dozens, possibly hundreds of layers of paint, each so thin that modern analysis struggles to distinguish them. He mixed pigments with unprecedented care, matching colors to optical principles he'd investigated in his notebooks. He understood that human skin wasn't a single color but a complex interaction of tones—reds from blood beneath, yellows and browns from melanin, modifications from ambient light. He captured this complexity in paint. But technique alone doesn't explain the painting's power. Something in Lisa Gherardini's expression—or in Leonardo's representation of it—transcends technical mastery. She's enigmatic, yes, but the enigma isn't cheap mystery. It's the complexity of actual human presence. People aren't single emotions. We're layers, contradictions, multiple feelings held simultaneously. Leonardo captured this. Lisa looks calm and amused, melancholy and knowing, present and distant. The expression doesn't resolve into a single reading because human expressions don't resolve. They shift, modulate, contain multitudes. He also made compositional choices that seem obvious in retrospect but were revolutionary at the time. Earlier portraits showed subjects in profile or stiffly frontal, hands rarely visible, backgrounds flat or abstract. Leonardo showed Lisa's hands—beautifully painted, relaxed but alert—and connected her to an expansive landscape. He eliminated the dividing line between near and far, blending figure and background into a unified space. The woman and the world she inhabits become inseparable. Francesco del Giocondo presumably wanted his painting delivered within a reasonable timeframe. He didn't get it. Leonardo kept the portrait, working on it intermittently, carrying it with him when he traveled. Years passed. Del Giocondo likely gave up on ever receiving it. Because Leonardo couldn't finish it. Or rather, couldn't stop working on it. Every time he looked, he saw adjustments to make. Another glaze around the eyes. Further softening of a shadow. A shift in the mouth's corner. The painting was never complete because representation was never complete. There was always another layer of subtlety to add, another nuance to capture. In 1506, Leonardo left Florence for Milan again, invited back by the French governor. He took the Mona Lisa with him. In 1513, he moved to Rome, seeking patronage from the Medici pope, Leo X. The painting came too. In 1516, at sixty-four, he accepted an invitation from King Francis I of France to become "first painter, engineer, and architect to the King," with a manor house at Amboise and a generous pension that demanded no specific output. Leonardo made the journey over the Alps, old and increasingly frail, and brought his notebooks, a few drawings, and three paintings. One of them was the portrait of Lisa Gherardini, twelve or thirteen years after he'd started it. He was still working on it. Still adding glazes. Still adjusting. The painting never returned to Francesco del Giocondo. Instead, it entered the French royal collection after Leonardo's death in 1519, purchased by Francis I for an enormous sum. It hung in Fontainebleau, then the Louvre, then—briefly—in Napoleon's bedroom, before returning to the museum. For centuries, it was admired but not uniquely famous. Leonardo's reputation rested more on The Last Supper and his theoretical writings. The Mona Lisa was one masterpiece among many. Then something shifted. Romantic-era critics began writing about the painting's mystery. In 1859, Théophile Gautier described Lisa's smile as suggesting "infinite tenderness and at the same time merciless bitterness." In 1869, Walter Pater published his famous description, calling her expression one of "unfathomable smile, always with a touch of something sinister." The painting became a symbol, a screen onto which viewers projected their own fascinations and anxieties. In 1911, an Italian handyman named Vincenzo Peruggia stole it from the Louvre, believing it should be returned to Italy. The theft made international headlines. When the painting was recovered two years later, it was world-famous. Millions lined up to see it. It became the most recognized painting on Earth, an icon transcending art history. The fame became its own phenomenon, eventually obscuring the painting itself. Today, visitors crowd around it in the Louvre, shooting photographs through bulletproof glass, reproducing an image that's already been reproduced billions of times. Most people spend less than fifteen seconds looking at it. They see the fame, the history, the myth—everything except the thing Leonardo actually painted. Which is a pity, because the painting itself—looked at carefully, without the noise of celebrity—is extraordinary. The way light models the face. The subtle animation of the features. The integration of figure and landscape. The sense of an actual person present, thinking thoughts you can't quite access, watching you with amusement or wisdom or sadness or all of these simultaneously. Leonardo spent years on it not because he was perfectionist in the conventional sense—striving for technical flawlessness. He spent years on it because he was trying to solve an impossible problem: how to represent the full complexity of human consciousness in paint. How to capture not just appearance but presence. Not just what a face looks like but what it means to be a person behind a face. He never completely solved it. But he came closer than anyone else. The painting remains unfinished—parts of the landscape are sketchy, some areas less resolved than others. Leonardo himself never considered it complete. But incompleteness was his natural state. Completion meant the end of investigation, and investigation was the point. Lisa Gherardini sits in the Louvre, half-smiling, watching millions of people who will never really see her, while Leonardo's genius—restless, curious, never satisfied—looks out through her eyes.

Machines That Won't Fly

Folio 858 recto in the Codex Atlanticus shows a mechanical wing, articulated joints labeled carefully, notes in mirror script explaining how it should move. A human straps in, operates foot pedals that drive the wing mechanism. The design is beautiful, ingenious, utterly incapable of lifting a person into the air. Leonardo filled his notebooks with flying machines. Not just one design but dozens, evolving over decades. Wings that flapped like birds. Fixed wings like bats. Rotating screws that pushed air downward—helicopters, essentially. Gliders that caught wind. Ornithopters where the pilot lay prone, operating wings with arms and legs simultaneously. Each design showed careful thought, observation translated into mechanism. Each was grounded in what Leonardo understood about bird flight, air resistance, leverage, and force. None could have worked. The problem was power. Human muscles can't generate sufficient force to lift human weight into sustained flight, not with the materials and designs available in the fifteenth century. Birds achieve flight because their muscle-to-weight ratio is optimized through evolution—hollow bones, powerful chest muscles, perfectly aerodynamic feathers. A human operating leather and wooden wings simply can't produce enough thrust. Leonardo suspected this but couldn't accept it. He calculated wing surface area needed for human weight. He designed mechanisms to amplify muscular force through levers and pulleys. He theorized about catching air currents to gain altitude. He was so close to understanding, yet the fundamental mathematics of flight eluded him because the mathematics required—calculus, physics of force and motion Newton would formalize in the next century—didn't yet exist. But here's what's remarkable: Leonardo's observations were correct. His principles were sound. He correctly identified that wings create lift by forcing air downward. He understood that larger surface area relative to weight improved flight capability. He recognized that wing shape mattered, that camber—the curve of a bird's wing—created aerodynamic advantages. These insights were accurate four centuries before the Wright brothers. The failures teach as much as the successes. Maybe more. Because Leonardo's willingness to pursue ideas that didn't work, to experiment with techniques that failed, to design machines that couldn't be built—this was essential to his genius, not incidental to it. He wasn't trying to produce functional products. He was investigating principles. Each failed flying machine was a hypothesis tested. Each collapse revealed something about force, materials, structural integrity. The process was the point. His military engineering followed similar patterns. He designed tanks—covered vehicles reinforced to resist cannon fire, with gun ports for soldiers to fire from inside. The drawings show circular or angular armored shells on wheels, powered by men turning cranks inside. They're imaginative, mechanically sophisticated, and mostly impractical. The weight of armor strong enough to stop cannonballs would require massive force to move. The heat inside would be unbearable. The visibility would be almost zero. But the concept—mobile armored firepower—anticipated modern tank warfare. He designed multi-barrel guns arranged in rows so that while one row fired, others could cool and reload, creating continuous firepower. It's the basic principle of the machine gun, though Leonardo's design used separate hand-loaded cannons rather than belt-fed ammunition. Still, the insight was valid: rapid, sustained fire required multiple barrels working in sequence. He drew giant crossbows, siege engines, bridges that armies could deploy rapidly. Some of these were practical; some purely theoretical. His notebooks contain designs for a scuba suit with a leather helmet and breathing tubes leading to the surface—functional in concept, though the leather would leak and the diver would struggle with pressure changes Leonardo didn't understand. He designed a submarine, recognizing that a sealed vessel could operate underwater if properly ballasted. These military inventions trouble modern admirers. How could Leonardo—vegetarian, bird-liberator, humanist—design weapons? He called war "a beastly madness," yet he designed instruments of war with the same care he applied to paintings. The contradiction dissolves when you understand his actual relationship to these designs. He was investigating principles of mechanics, not optimizing murder. The military engineering was intellectual exercise, demonstrating capabilities to patrons who controlled funding. There's little evidence he pushed to see his weapons built. He spent far more energy on canal systems and architectural projects than on actual military applications. What he loved was the problem itself. How would you create a vehicle that could withstand attack? What mechanism would allow continuous fire? How could humans move underwater? These were puzzles, challenges to his understanding of physics and materials. The solutions existed first in his mind, then on paper. Whether they were constructed mattered less than whether they could be imagined. His architectural designs show the same pattern. He sketched plans for domed churches, playing with how classical proportions could be adapted to Christian sacred spaces. He designed villas, fortifications, urban planning projects. Most remained paper projects, but the investigations fed into practical work. When he consulted on Milan's cathedral, his theoretical explorations of structure and proportion translated into specific recommendations. He designed a self-propelled cart—essentially a robot—powered by springs. Studies of the surviving drawings suggest it could have worked, if built with precision. Probably it was intended as an automaton for court pageants, but the principle—stored energy released to create motion—was sound. He invented a machine for testing tensile strength of wires, anticipating materials science. He designed diving bells, dredging equipment, machines for grinding lenses. He drew an odometer for measuring distances traveled. He sketched a continuously variable transmission—a mechanical insight that wouldn't be applied to automobiles until the twentieth century. Some designs were purely fanciful. A lion that walked across a room and opened its chest to reveal lilies—this Leonardo actually built for a pageant celebrating the French king. It worked, apparently, becoming legendary among witnesses. But it was theater, not serious engineering. Or rather, it was both: an investigation of mechanical motion dressed as spectacle. The notebooks contain failures and fantasies alongside genuine innovations. Leonardo didn't distinguish sharply between them because he was always teaching himself. A design that couldn't work still revealed why it couldn't work, and that knowledge was valuable. A fanciful machine still explored real mechanical principles. This is alien to modern engineering culture, which separates research from application, pure science from technology. Leonardo operated in a Renaissance world where knowledge was unified, where investigating nature and building machines and creating art were aspects of a single inquiry. He studied bird flight not to build airplanes but to understand flight. If understanding led to designs that couldn't be realized, that didn't diminish the understanding. His contemporaries found this frustrating. They wanted deliverables. Leonardo gave them sketches, principles, insights, questions. He designed the greatest equestrian statue ever conceived—twenty-four feet of rearing horse and rider—then watched it destroyed before casting. He proposed river diversion projects that were technically feasible but politically impossible. He drafted treatises that remained unpublished, organized only loosely, full of observations that wouldn't be verified until modern science caught up. The unbuilt machines, the unfinished paintings, the unpublished treatises—they all point to the same quality. Leonardo valued investigation over completion, process over product, understanding over demonstration. His genius wasn't just in what he created but in how he thought: following connections, testing hypotheses, refusing to accept conventional answers, pushing toward deeper principles even when practical applications eluded him. The flying machines didn't fly. The paintings stayed unfinished. The scientific insights weren't widely disseminated during his lifetime. But the investigations were real. The observations were accurate. The principles were sound. Leonardo was asking the right questions centuries before the rest of the world was ready for the answers. His notebooks sat in private collections for hundreds of years, scattered across Europe, unread and unappreciated. When scholars finally began seriously studying them in the nineteenth century, they found anticipations of modern technology everywhere: helicopters, tanks, parachutes, submarines, ball bearings, solar power, plate tectonics. Not fully developed, not perfectly accurate, but recognizable. Leonardo's mind had ranged four centuries ahead, imagining futures he couldn't realize. The machines that won't fly still teach us to imagine flight. The incomplete investigations still demonstrate how to investigate. The failures still inspire, because they show a mind refusing limits, asking questions without regard for whether answers were possible. That restless questioning was Leonardo's real invention, more important than any device or image. A way of being curious that didn't stop at conventional boundaries, that connected everything to everything else, that valued understanding for its own sake. He didn't just draw flying machines. He showed humanity how to dream of flight.

What He Left Behind

Leonardo died on May 2, 1519, at Clos Lucé in Amboise, France, in the manor house King Francis I had given him. He was sixty-seven. Accounts suggest he suffered a stroke some months earlier that partially paralyzed his right side—though being left-handed, he could still draw. The king, who genuinely loved Leonardo, visited frequently. There's a romantic legend that Leonardo died in the king's arms, but Francis was elsewhere that day. Still, the king mourned publicly, calling Leonardo "a father." The artist left his notebooks and drawings to Francesco Melzi, his devoted assistant and companion. Melzi transported the massive collection back to Italy, where he attempted to organize it into a coherent treatise on painting. It was a sisyphean task. Leonardo's notes were scattered across thousands of pages, written in mirror script, crammed into margins, jumping between topics without transition. Anatomy mixed with art theory. Hydraulics interrupted geometry. Half-finished thoughts trailed off into diagrams. Melzi managed to compile the Treatise on Painting from fragments, but the rest defeated him. After Melzi's death in 1570, the notebooks scattered. His heirs didn't understand their value. Some were sold to collectors. Some were stolen. Some were lost. Pages were removed and sold separately. Codexes were broken apart and reassembled incorrectly. Over centuries, Leonardo's papers ended up in libraries and private collections across Europe: the Royal Library at Windsor Castle, the Louvre, the British Museum, Milan's Biblioteca Ambrosiana, the Institut de France. Bill Gates purchased one codex—the Codex Leicester—for $30.8 million in 1994. The pages that survive represent perhaps a quarter of Leonardo's total output. The rest—three-quarters of his life's investigation—is simply gone. What survived sat mostly unread for centuries. Leonardo's mirror writing was difficult. His lack of formal organization was frustrating. His insights were scattered among observations that seemed trivial or incomprehensible. Scholars occasionally dipped into the notebooks, but systematic study didn't begin until the nineteenth century. Then, as modern science and engineering developed, Leonardo's prescience became apparent. His anatomical drawings were more accurate than anything produced until the 1800s. His observations about geology, hydraulics, optics, and mechanics anticipated later discoveries. His mechanical designs previewed inventions that wouldn't appear for centuries. This created a mythology that Leonardo was a prophet, a mind from the future trapped in the Renaissance. But that misunderstands what he actually was. Leonardo wasn't magically seeing the future. He was observing the present with extraordinary care. His insights came from looking closely, questioning assumptions, testing hypotheses. The reason his work seems prophetic is that he was doing science before the scientific method was formalized—and doing it better than many who came later. His artistic legacy proved easier to disseminate, though complicated by his habit of leaving works unfinished. The Last Supper, despite its deterioration, remained visible and influential. The Mona Lisa entered the French royal collection and eventually became the world's most famous painting. But many works were lost or remained incomplete. The Adoration of the Magi sat unfinished in a monastery until it was moved to the Uffizi. The Battle of Anghiari survived only in copies; the original was painted over or destroyed. The giant equestrian statue existed only in preparatory drawings. Of paintings confidently attributed to Leonardo's own hand, perhaps fifteen survive. For an artist who lived to sixty-seven and was celebrated as the greatest painter of his age, that's shockingly few. Michelangelo, by comparison, left hundreds of works. Raphael painted dozens of major compositions in a career cut short at thirty-seven. Leonardo's output was constrained by his refusal to separate art from investigation, his need to understand before representing, his inability to consider a work truly finished. Yet those fifteen paintings transformed art. They demonstrated that painting could capture psychological complexity, that figures could inhabit space naturally rather than being pasted onto backgrounds, that light and shadow could model forms without hard edges, that human emotion could be represented with subtlety and specificity. Later artists studied Leonardo's techniques obsessively. Raphael borrowed his compositional strategies. The Venetians adopted and refined his sfumato. The Baroque painters built on his understanding of dramatic lighting. His engineering and scientific work had less immediate impact because it wasn't published. If Leonardo's notebooks had been widely available in the sixteenth century, the development of technology might have accelerated dramatically. But they weren't. His insights remained private, lost in scattered pages of mirror writing. So the world had to rediscover what Leonardo already knew: how blood circulates, how fossils form, how air behaves as a fluid, how machines can amplify force. The real tragedy isn't that Leonardo left so much unfinished. It's that what he did finish—the investigations, the observations, the connections he mapped between art and science—wasn't transmitted to the generations that followed. His holistic approach to knowledge, his refusal to recognize boundaries between disciplines, his insistence on observation over authority—these were radical ideas that the Renaissance wasn't quite ready to absorb. Instead, knowledge became increasingly specialized. Art and science separated into distinct domains with different methodologies and goals. The unity Leonardo embodied—where studying anatomy improved painting, where observing water informed engineering, where everything connected to everything else—fragmented into disciplines that barely communicated. Modern education reflects this fragmentation. We train scientists and artists separately, as though they're investigating different realities. We reward specialization, narrow expertise, deep knowledge of specific fields. Leonardo's approach—broad curiosity, following connections across domains, valuing understanding over credentials—seems impractical, undisciplined, amateur. But the twenty-first century is rediscovering what Leonardo knew: reality is unified. Climate science connects to economics, biology, politics, engineering. Medicine requires understanding of chemistry, genetics, behavior, social systems. Technology development needs not just engineering but design, psychology, ethics. The problems humanity faces don't respect disciplinary boundaries. Leonardo's legacy isn't specific inventions or paintings, though those matter. It's a way of being curious. A refusal to stop at conventional limits. An understanding that everything is connected, that art informs science and science enriches art, that observation matters more than authority, that questions are more valuable than premature answers. He showed that genius isn't about having all the answers. It's about asking better questions, looking more carefully, following connections others miss, remaining perpetually unsatisfied with surface explanations. It's about being willing to fail, to leave things incomplete, to pursue understanding even when it doesn't lead to tidy products. The world remembers Leonardo for the Mona Lisa's smile, for The Last Supper's drama, for the iconic drawing of the Vitruvian Man. These are worthy monuments. But the deeper legacy is harder to see: a way of thinking that integrated rather than separated, that valued process over product, that remained eternally curious about everything. He filled notebooks with questions that would take centuries to answer. He designed machines that couldn't be built with his era's technology but that demonstrated correct principles. He painted faces so alive they seem about to speak. He dissected corpses to understand muscles he would then paint with unprecedented accuracy. He watched water spiraling behind stones and saw the same patterns in hair, in plants, in the cosmos itself. Nothing was finished because nothing could be finished. Understanding was infinite, curiosity inexhaustible, nature's complexity bottomless. Leonardo didn't fail to complete his work. He succeeded in demonstrating that completion is an illusion, that investigation has no endpoint, that every answer opens new questions. The unfinished symphony isn't a failure. It's an invitation—to keep looking, keep questioning, keep connecting, keep wondering. Leonardo left us thousands of pages of observations and still it wasn't enough, could never be enough, because the world's complexity exceeds any single mind's capacity to capture it. But we can try. We can observe carefully. We can question assumptions. We can refuse to accept disciplinary boundaries as real limits. We can follow our curiosity wherever it leads, even into apparent tangents, trusting that everything connects if we look deeply enough. That's Leonardo's gift: not answers, but a way of asking. Not completion, but the courage to begin. Not certainty, but a demonstration that uncertainty, approached with rigor and wonder, is where understanding lives. The notebooks scattered across Europe contain investigations that will never end, questions that will never be exhausted, a mind that refused to stop looking. Leonardo's unfinished symphony continues playing, and we're invited to add our own notes, our own observations, our own curious investigations into the infinite complexity of existence. He showed us how. We just have to be willing to begin, knowing we'll never quite finish, and that the never-finishing is the point.