Moaning Cavern is a commercial cave featuring California's "longest vertical chamber," touted as big enough to fit the Statue of Liberty. The earliest explorers were actually prehistoric victims, who fell to their deaths down California's "longest vertical chamber" over a period of several hapless centuries. The bones of 100 of these Cro-Tourists have been found in the cave.
The "moaning" comes from an eerie sound heard in places created by water dripping into flowstone formations, not from the spirits of unhappy, accident-prone cave-people.
The cave was first probed for gold by miners in 1851, but it turned out to be just a plain old cave. In 1919 Moaning Cavern was "rediscovered" and opened for paying tours by the public in 1920. A 100-ft spiral staircase with 144 stairs, built in 1922 out of the hull of a World War I battleship, is still used by visitors today. Moaning Cavern's formations have edgy monikers such as "Godzilla's Nostril" and "Meat Grinder," which suggests that its more contemporary employees have indulged in some renaming.
The cave offers a family walking tour as well as an Adventure cave excursion in spelunker jumpsuits and helmets. A recent addition to Moaning is an outdoor activity -- a 1.5 mile long zipline that will let visitors speed along its length hanging above the hillsides near the cave.