From the nationalgeographic.com article:
Colorful mosaics spiral across the vaulted ceiling of a grotto that was unveiled today as the likely place where ancient Romans believed that a she-wolf suckled their city’s legendary founders.
In January archaeologists announced that the sacred cave, known as the Lupercale, had been found during excavations of Emperor Augustus’ palace on the Palatine, a 230-foot-tall (70-meter-tall) hill in the center of Rome.
According to Roman myth, a female wolf nursed the abandoned twins Romulus and Remus in the Lupercale. The grown brothers are said to have founded the Eternal City at the site on April 21, 753 B.C.
Also check out this Photo Gallery of Ancient Rome Reborn in 3-D.