Rome is known as the city of how many hills?
Upon its incorporation, the ancient city of Rome was built atop seven hills — Aventine, Caelian, Capitoline, Esquiline, Palatine, Quirinal, and Viminal — which were protected within the city's Servian Walls, a fortification constructed in the fourth century BCE. Though the city limits have since expanded in modern times, those original seven hills still lend themselves to Rome's nickname.
Source: Italofile