Catacombs of Rome
The Catacombe di Roma (Catacombs of Rome) are found in Assassin's Creed: Brotherhood and are located under the city of Rome. They were built in the 2nd century when Christians needed more space to secretly bury their dead, as Christianity was illegal at the time. In Assassin's Creed: Brotherhood it appears as a Lair of Romulus. The entrance to the catacombs is located right next to the Piramide Cestia.
The Lair of Romulus must be completed within 8 minutes to achieve full synchronisation. Ezio had to follow the torches on the wall to find the Shrine of Romulus. There was a presumably bottomless hole that Ezio had to drop and grasp the wall to find the entrance. Near the end, Ezio was attacked by several Followers of Romulus, but they were easily dispatched. Ezio finally reached the Shrine and took the Scroll of Romulus in it.