For nearly three decades, the mystery of the disappearance of three Americans who descended into the “Devil’s Pit,” the dangerous tunnel at Limanakia of Vouliagmeni, remained unsolved.

It is proof of just how dangerous the underwater passage is, as even today it has not been fully mapped.

At the same spot where, since Sunday, a search is underway for the 34-year-old diver, in September 1978 two American servicemen stationed at the U.S. base in Elliniko and another woman attempted to explore the area.

They were 32-year-old sergeant Donald Mishand, 21-year-old airman Mark Granford, and the latter’s 20-year-old sister, Joan. None of them returned to the surface.

Major efforts were organized to locate them, but without result. An initial large-scale rescue attempt took place in November 1978, while in 1989 cave divers recovered only a tank and some personal items. Their remains were finally located in 2006 and identified the following year.

See photos from the recovery of the remains in 2006:

They were found in crevices of the underwater tunnel, where strong currents had swept them until their oxygen ran out.

A dangerous pit
The underwater pit at the second Limanaki of Vouliagmeni is located just a few meters from one of the most popular coastal spots, which attracts thousands of visitors in the summer.

It is the opening of a tunnel with a diameter of 3 meters, located at a depth of 11 meters. A buoy marks its position for swimmers, roughly in the middle of the cove.

Those who have moved through the tunnel report that it initially extends horizontally, but at one point has a steep downward slope. This is where the current becomes extremely strong and highly dangerous for divers, and darkness prevails.

The length of the tunnel is about 30 meters, with particularly dangerous currents around 16 meters, where the tunnel “pulls” the diver downward. It then leads to the entrance of a narrow underwater passage that ends in a cave of unknown dimensions.

Exploration has only reached 150 meters. It is possible that the entire system is connected to Lake Vouliagmeni.

In the 1980s, the Coast Guard installed a protective net at the site to prevent dangerous dives. There is also a warning sign reminding that “Beyond this point, there is nothing worth seeing that is more valuable than your life.”

A unique documentary about the “pit”
In 2018, the diving team of Antonis Grafas organized an expedition to explore and map the underwater cave.

They ultimately managed to reach a distance of 145 meters, a mission which, as Grafas himself says, was one of the most difficult both physically and psychologically. “We do not advise or encourage anyone to enter the cave, and everyone bears personal responsibility for their diving choices,” he notes on his website.

The result of the missions was both a map showing the explored part of the cave and a documentary about the “Devil’s Pit.”