You are standing at the entrance of the biggest Roman imperial bath. As the name implies, Terme di Diocleziano was built for Diocletian in 306 AD. He was the Emperor of the Roman Empire from 284 to 305 when he voluntarily abducted his title. Yet it was Maximian, while the co-emperor and ruler of the Western Empire, who commissioned the Baths of Diocletian for his partner. This complex on Viminal Hill is enormous covering 32 acres. Among the features were hot (caldarium) and cold (frigidarium) pools inside lavish rooms, dressing rooms (apodyteria), gymnasiums, circular social halls, two libraries and intimate private rooms. Since the thermae was abandoned in 537 AD, sections have been repurposed as a church, a basilica, planetarium and a warehouse. The Baths of Diocletian is now part of the National Roman Museum (Museo Nazionale Romano).