Caligula party boats.

Local fishermen had known of the Caligula party boats for centuries, as they were partly visible in low water. They'd been known since at least the 15th century. The emperor Caligula's excesses extended to high society parties out on the water, Roman style. Who knew who was doing who out there, but that it was happening is guaranteed.

But in 1927, Mussolini ordered his military engineers to drain the lake so that the boats could be recovered.

The biggest one was 240 feet long and 80 feet wide, a massive platform almost as big as a football field.

Among the costly adornments were gilded copper roof tiles. Imagine a sunrise on the water, mountains in the background, the roof of the boat's superstructure looking like SOLID GOLD, gleaming in the light of the new day.

Lots of artifacts remain, but the boats themselves burned in 1944, as Italy and ally Germany retreated in the face of an American advance. Nobody knows whether American artillery burned them or the Nazis set fire to them as they often did in retreat, to slow the advance of the opponent.

A few photographs remain. Mussolini did get them extracted from the water and put on display, but that didn't last long.