[46, Boboli Gardens, Florence] By the year 1500, what had begun in Florence a century earlier was coming to a peak: an exciting time known as the High Renaissance. Italy was thriving, with a huge appetite for art. Artists who in earlier times had toiled as anonymous craftsmen were now famous and well-paid. Three towering artists — all with Florence connections — brought the Renaissance to its culmination and then helped spread it throughout Italy and beyond: Leonardo, Michelangelo, and Raphael.

[47, Leonardo da Vinci, 1452–1519] Leonardo da Vinci was the ultimate well-rounded "Renaissance man": inventor, engineer, sculptor, and painter. Always asking why and how, he filled up entire notebooks with sketches and ideas.

[48, angel by Leonardo in Verrocchio's Baptism of Christ, Uffizi Gallery, Florence] When he was an apprentice — just a boy — Leonardo painted this beautiful angel, with curly hair, rosy cheeks, and innocent gaze.

[49, Portrait of Ginevra Benci; Madonna of the Carnation, 1475] Welcomed as a part of the elite and enlightened Medici circle, young Leonardo was already developing the elements of his signature style: meditative Madonnas, a playful baby Jesus, amid a hazy, mysterious backdrop.

[50, Annunciation, 1472, Leonardo da Vinci, Uffizi Gallery, Florence] His obvious talent as an artist along with his mastery of engineering and architecture put him in high demand. Leonardo journeyed to Milan, where he enjoyed the generous patronage of that city's answer to the Medici, the Sforza family.

[51, Leonardo's Horse for Duke of Milan, designed 1482, built 1999] He donned his engineer's cap and laid out Milan's system of canals, complete with locks. And he designed the largest equestrian statue in the world — recently cast in bronze from his drawings.

[52, Last Supper fresco, 1498, Leonardo da Vinci, Church of Santa Maria delle Grazie, Milan] One of Leonardo's greatest masterpieces decorates a dining hall in a Milan monastery. The Last Supper. It's Jesus' last meal with his disciples, just before he'd be crucified. Leonardo packs the scene with psychological tension. He captures the moment Jesus says, "One of you will betray me," and the apostles, huddling in stressed-out groups of three, wonder, "Lord, is it I?" In this agitated atmosphere, only the traitor Judas — clutching his 30 pieces of silver — is not shocked.

[53] Leonardo's use of linear perspective gives the scene an extra punch. He makes the painted room an extension of the actual room, with shadows as if lit by the real room's windows. All the lines of perspective converge toward the center, sub-consciously drawing you to the powerful emotional focal point — Jesus. His calm expression makes it clear that he knows the painful sacrifice ahead — and accepts it.

[54, Virgin of the Rocks, Leonardo da Vinci, National Galley, London] Constantly evolving, Leonardo perfected his signature sfumato, or "hazy," technique — the soft outlines of the faces…the mysterious mountains fading in the mist. Using what's called "atmospheric perspective," he showed depth by understanding how colors become muted when more distant. He managed to create scenes that looked perfectly natural…but had an underlying geometry that reflected the order seen in nature.

[55, Mona Lisa, 1506, Leonardo da Vinci, The Louvre, Paris] And with his Mona Lisa, all these techniques came together marvelously.

[56] Lisa, a woman from Florence, rests easily, as if sitting in a window looking out. Remarkably realistic and relaxed, her body is a solid pyramid, turned slightly at an angle, so we can appreciate its mass. With its hazy background emphasizing the depth, the overall mood is one of serenity and harmony, but with an element of mystery. Especially the enigmatic smile. Leonardo's hazy sfumato blurs the edges. That's why, try as you might, you can never quite see the corners of her mouth. Is she happy? Or sad? Everyone sees her differently.

[57] For me, this painting sums up the Renaissance: balance, confidence, and humanism — the age when the common individual — Mona Lisa — becomes art-worthy.

[58] In his long career, Leonardo da Vinci — by combining art and science — revolutionized our notion of art. He was the epitome of perhaps the highest compliment an artist can receive — a true Renaissance genius.