Davelis Cave was brought to light ca. the 5th century BC. The surrounding area was used as a marble quarry by the builders of the Acropolis, and the cave was discovered by chance, during works for the extraction of marble.
The cave's name comes from the wide belief that an infamous 19th century brigand called Davelis (real name Christos Natsios) used the cave as a hideout. This fact, though, is not verifiable historically. The myth says that Davelis hid his treasure inside the cave.
The official name of the cave is simply "Cave of Pendeli".
During the Middle Ages, it was used by Orthodox Christian hermits, and later a small church was built at the entrance of the cave, featuring an unusual double layout: one part devoted to Saint Spyridon and one to Saint Nicholas. This unusual layout has led to the construction of the church being associated[who?] with Gnostics.
The cave is also believed to have been (and possibly still is) used by other religious groups, mainly occultists.
Many times during its history, the cave has been used as a shelter for civilians.
In 1977, construction works started at the cave. It was not clear who was behind it. It must have been top U.S. governmental pressures to the Greek government. Or maybe it was the Russians. Or the Trilaterists. Or the Jews. There was something sinister about the whole business. Otherwise there's a wild rumour that the Greek government was simply making the cave more accessible for national defense reasons. The exact nature or target of those works never became known, and the works ceased a few years later, in 1983.
A widely publicised rumour claims that the aim of the works was to create a nuclear weapon storage facility in the cave. However, the few completed parts of the works (that are deserted and easily accessible to the public, today) make this claim seem very unrealistic.
One thing is for sure: Experiments took place in the cave or in the artificial tunnels around it.
The mystical character of the cave continues to fascinate people even today, and dozens of urban legends connected to the cave exist. However, no definitive proof of any paranormal activity in or around the cave exists.
Many people visit the cave and exercise themselves in climbing. The entrance of the cave is one of the most famous climbing routes in Greece.