Filippo Brunelleschi designed this basilica, as well as that of Santo Spirito in the Oltrarno, in the 15th century. He never lived to see either finished. The two interiors are similar in design and effect. San Lorenzo, however, has a grid of dark, inlaid marble lines on the floor, which considerably heightens the dramatic effect. The grid makes the rigorous geometry of the interior immediately visible, and is an illuminating lesson on the laws of perspective. If you stand
in the middle of the nave at the church entrance, on the line that stretches to the high altar, every element in the church—the grid, the nave columns, the side aisles, the coffered nave ceiling—seems to march inexorably toward a hypothetical vanishing point beyond the high altar, exactly as in a single-point-perspective painting. Brunelleschi's Sagrestia Vecchia (Old Sacristy) has stucco decorations by Donatello; it's at the end of the left transept.
Piazza San Lorenzo, Florence, 50123, Italy