This, the emperor's private residence, was built on two levels, with rooms leading off a peristilio (peristyle or porticoed courtyard) on each floor. You can't get down to the lower level, but from above you can see the basin of a big, square fountain and beyond it rooms that were paved with coloured marble.
In 2007 a mosaic-covered vaulted cavern was discovered more than 15m beneath the Domus. Some consider this to be the Lupercale, a cave believed by ancient Romans to be where Romulus and Remus were suckled by a wolf.
