The name of the village comes from "Nemus Dianae", sacred wood dedicated to Goddess Diana, hunting goddess, lady of the woods and protector of women. The Temple of Goddess Diana stood at the banks of Lake Nemi, a basin of volcanic origin and represented a renowned place of worship for the people of the whole Roman area. The Temple of Diana Nemorensis hosted crowds of pilgrims coming from more or less neighboring places who went to worship the Goddess and to seek healing and fertility. Today archaeological excavations, begun in the seventeenth century, mostly held by foreign amateurs and scholars, have discovered the findings found in the Museums of Europe. On the spot you can, however, observe part of the ancient perimeter of the structure. .
Since ancient times, Lake Nemi was the subject of a legend about two fabulous ships of gigantic dimensions, built in Roman times, perhaps containing treasures that would have been buried at the bottom of the lake for mysterious reasons; the ships were constructed by Caligula, used as floating houses and then destroyed and sunk. The fishermen in the medieval age brought back the first remains of the ships; true recovery was tempted from 1446, but only between 1928 and 1932 the two hulls were extracted and a Museum on the shore was inaugurated to host them. However, the very rare relics, important "witnesses" to the unexpected Roman naval perfection, were destroyed by war events on May 31, 1944, for an arsonist whose causes are still controversial. Nevertheless, the Nautical Museum is still of great interest for the many finds it conserves.