The arena floor of the Colosseum was the wooden stage where gladiators fought, wild animal hunts took place, and public spectacles were held. Covered with sand to absorb blood and improve footing, it concealed an intricate network of underground chambers and passageways that housed performers, animals, and stage machinery before they emerged into the arena. Today, a reconstructed section of the arena floor allows visitors to experience the amphitheater from the perspective of those who once stood at its center.

The Mamertine Prison (Carcer Tullianum) is the oldest prison in ancient Rome, built in the 7th century BC at the foot of the Capitoline Hill near the Roman Forum. It was used to imprison Rome's most important enemies before execution, including defeated kings and military leaders. According to Christian tradition, Saints Peter and Paul were held here before their martyrdom, making it a site of great historical and religious significance. The prison consists of two underground chambers, with the lower Tullianum serving as the oldest and most secure cell.