Where the famous Lake Vouliagmeni ends, starts a labyrinth underwater cave that communicates with the sea with various galleries, and which has been explored at a length of 3.123 meters while the cave’s end remains elusive. It is said that the existence of the cave was identified by the Germans, who during the occupation had attempted to explore it, through a select group.
Official Greek research launched in 1988 through a program of the Ministry of Culture with funding from the Municipality, brought to light new impressive data about the cave. The head of the investigation was the Swiss cave diver Jean-Jacques Bolang, who, following an unknown narrow passage, discovered a huge underwater area with a capacity of 1.200.000 cubic meters. Bolange's partner, Luigi Casati, brought to light an oversized stalagmite that is 105 meters deep.
Among its 14 tunnels is the largest underground tunnel in the world with a length of 800 meters while its depth reaches 80 meters. Exploring it is difficult and dangerous, as it has lanes that form a 4,3 kilometer labyrinth. Also, the discovery of a huge stalagmite in the cave creates new data in research on the formation of the Mediterranean.
There are eight missions in the area. A total of eight divers have lost their lives while diving into the cave. The reasons were both lack of experience and inadequate equipment. But there is also a legend that a fairy wants to live on the seabed, which traps young men. The reality is different, and authorities have banned access to the cave for public safety reasons since 1995.