The ancient structure known for its use during gladiatorial contests is the Colosseum, located in Rome, Italy. Constructed between 70 and 80 AD, it was designed to host a variety of public spectacles, including gladiatorial games, animal hunts, and mock sea battles. The Colosseum could hold tens of thousands of spectators, becoming an iconic symbol of ancient Rome and its architectural engineering prowess. Gladiators would fight in the arena under the watchful gaze of the Roman populace, serving as both entertainment and a demonstration of power. The Colosseum remains one of the most visited historical sites today.