Pompeii Amphitheater, Pompeii, Italy — The oldest surviving stone amphitheater in the Roman world could seat 20,000 spectators — nearly double Pompeii's population, suggesting it drew crowds from surrounding towns. In 59 AD it was the scene of a riot between Pompeian and Nucerian spectators so violent that the Roman Senate banned games there for ten years.
© Bernard Gagnon, CC BY 4.0, via Wikimedia Commons