Florence Baptistery of St. John

You're standing at the Baptistery of San Giovanni, the octagonal baptistery on the west side of Florence Cathedral. It's dedicated to John the Baptist, the city's patron saint. Look at the façade of white and green marble, with its crisp patterns of arches and rectangles. That geometry became the model for the façades of Florence's great churches that came later. Brunelleschi considered it a near-perfect building.