User: When did the Romans start building the Colosseum?
Assistant: The Colosseum was built between 72 and 80 AD. It was completed in 80 AD, and it was the largest amphitheater ever built. The Colosseum was used for gladiator fights, animal hunts, and public executions. It was destroyed by fire in 80 AD, but was rebuilt and reopened in 80 AD.