The famous Roman structure used for gladiatorial contests and public spectacles is the Colosseum, also known as the Flavian Amphitheatre. Completed in AD 80, the Colosseum was an architectural marvel, capable of seating tens of thousands of spectators. It hosted a variety of events, including gladiatorial battles, animal hunts, and mock sea battles, showcasing the might of the Roman Empire. The Colosseum represents the cultural, architectural, and social ingenuity of ancient Rome and continues to be a symbol of the empire's enduring legacy.