Basilica di Sant'Apollinare in Classe

This early Christian basilica outside Ravenna is famous for the shimmering sixth-century mosaic filling its apse, showing a green paradise and a jewelled cross. Built when the city was a Byzantine capital, it retains a tall round bell tower and rows of ancient sarcophagi along the nave. A distinctive detail is the apse mosaic's field of trees, birds and sheep surrounding a robed figure, a vision of Eden rendered in glittering glass that has survived almost unchanged for fifteen centuries.