Church of San Zeno

This guide to the Church of San Zeno in Pisa starts with an odd detail underfoot, a floor that dips from brick to broken stone, and follows the excavation that explained it. It traces the layers archaeologists found beneath the nave: an earlier building with three rounded apses, blocks of reused Roman stone from a ruin locals called the caves, and centuries of religious communities who each rebuilt on top of the last. Look up at the facade too, where ceramic basins nearly a thousand years old were mortared in rather than made on site.