Basilica of San Lorenzo

The Medici family's parish church has an unfinished brick facade, and that's one of the most fascinating things about it. Michelangelo designed a grand marble front in the 1510s, but it was never built — the rough, exposed brick that greets you today has been "temporary" for five hundred years. Pope Leo X (himself a Medici) commissioned the design, and Michelangelo even went to the Carrara quarries to select the marble, but the project collapsed amid cost overruns and political upheaval.

Inside is a completely different story. Brunelleschi redesigned the church between 1421 and 1442 in his signature style — grey pietra serena stone against white plaster, perfect proportions, classical columns — creating one of the purest expressions of Renaissance architecture in existence. The Medici paid for everything, and they made sure everyone knew it: the family pew, the family tombs, and eventually the entire Medici Chapel complex grew from this building like a marble tumor of dynastic ambition.

The Old Sacristy, also by Brunelleschi, contains a small astronomical dome that accurately depicts the night sky over Florence on July 4, 1442 — the date is debated, but it's one of the oldest accurate representations of the heavens in art. Donatello contributed the bronze pulpits in the nave, his last works, so expressive and raw that some panels were left unfinished at his death. The Laurentian Library above, designed by Michelangelo with its revolutionary staircase, is a masterwork of Mannerist architecture.

San Lorenzo is where the Medici story begins and ends — their first patronage of Brunelleschi, their final tombs in the chapels behind. No single building tells their story more completely.