The bathing area of Caracala was the second largest bathing area in Rome at the time, and the first was the bathing area of Diocletian next to the railway station (which was available for 3,000 people at the same time). The bathing area of Caracala was a comprehensive leisure centre with a library, shops and gardens. The underground chamber of the bathing chamber has a pipeline of 9.5 kilometers long, and nearly 1,000 slaves work hard to watch the intricate pipeline system in the tunnel every day. At that time, there were a million people in Rome, of whom 300,000 were slaves.