What is mamertinum?

Mamertinum was a prison located in the ancient Roman city of Rome. It was also known as the Tullianum and was a place where state criminals, including high-ranking officials, were incarcerated. The prison was located beneath the Capitoline Hill and was considered one of the most severe and inhumane prisons in Rome. It was built in the 7th century BC and continued to be used until the 6th century AD. The Mamertinum consisted of two levels; the upper level was used for storage, while the lower level was where prisoners were held. The lower level was a damp, dark, and cramped space that was accessible only by a trapdoor. The only source of light and air was a small hole in the ceiling. Some of the notable prisoners who were held at the Mamertinum include Saint Peter, the apostle, and Jugurtha, a king of Numidia. Today, the Mamertinum is a popular tourist site and is open to the public.