Lake Nemi (Italian: Lago di Nemi) is a lake located in Italy.
Lake Nemi is a small volcanic lake situated about 30 kilometres south of Rome. It is named for Nemi, the largest town in the vicinity and is best known for the huge sunken Roman ships at its bottom, the largest of which are believed to have been elaborate floating palaces during the 1st century.
The ships have technology aboard which was believed to have been invented only recently, including complex heating systems and bath plumbing.
During the early 16th century, Cesare Borgia had established a weapons factory near the lake which manufactured chariot-mounted machine guns. In 1502, the Assassin Ezio Auditore da Firenze broke into the factory, burned the plans for the machine and destroyed the only two prototype machines in existence.