Flavian Amphitheater at Puteoli

The Flavian Amphitheater, located in Pozzuoli, is the third-largest Roman amphitheater in Italy. Only the Roman Colosseum and the Amphitheatre of Capua are larger. It was likely built by the same architects who previously constructed the Roman Colosseum. The name "Flavian Amphitheater" is primarily associated with the Roman Colosseum.

Description via Wikipedia. Coordinates and heritage data from the Atika atlas.