Welcome to Piazza del Duomo, the spiritual and artistic beating heart of Florence. As you stand here, you are looking at the Cattedrale di Santa Maria del Fiore, better known simply as the Duomo. Before you do anything else, take a slow spin. Notice how the building seems to glow with its vibrant patterns of white marble from Carrara, green from Prato, and pinkish-red from Siena. This massive structure was intended to be one of the largest in the world, a statement of Florentine power and pride that began way back in the year twelve ninety-six under the architect Arnolfo di Cambio. It is so large that it can hold up to thirty thousand people at once. You are walking in the footsteps of the greatest minds of the Renaissance, and you are about to discover why this building changed the world of architecture forever.