Ravenna is a city in Emilia-Romagna, Italy. It's known for the colorful mosaics adorning many of its central buildings, like the octagonal Basilica di San Vitale, the 6th-century Basilica di Sant'Apollinare Nuovo and the cross-shaped Mausoleo di Galla Placidia. North of the center, the Mausoleo di Teodorico built in the 6th century for King Theodoric the Great, is a Gothic, circular stone tomb with a monolithic dome.