The Roman amphitheatre of Catania sits half-sunk into Piazza Stesicoro, only a fraction of its full ellipse visible above ground. The rest runs under the surrounding buildings — this was one of the largest amphitheatres in the Roman world after the Colosseum, large enough to seat around fifteen thousand.
The visible portion shows the lava-stone construction and the vaulted corridors that supported the seating. The whole site is fenced off but visible from the surrounding pavement, and well lit at night. It is a useful reminder that the apparently baroque city has Roman bones.