Baths of Trajan (Rome)

Italy / Lazio / Rome
 Roman Empire, ancient ruins, tourist attraction
Baths of Trajan (Thermae Traiani), begun in 104, were a massive Roman bathing and leisure complex, covering some of the ruined golden palace of Nero (Domus Aurea). The massive underground cistern, capable of storing no less than 8 million litres, is still there, known as the Sette sale.
Wikipedia article: http://en.wikipedia.org/wiki/Baths_of_Trajan
Nearby cities:
Coordinates:   41°53'32"N   12°29'45"E