The Rock Church of St. Basil is one of Gravina's small cave churches, probably dating from the 10th century. Its four-nave interior is cut into the rock, with traces of frescoes still visible on the walls.
It is a compact stop, but it helps explain why Gravina's ravine and old quarter feel layered rather than merely pretty. Pair it with San Michele delle Grotte and the cathedral for a fuller sense of the town's cave-church heritage.