Work crews digging a new uphill water pipeline to Jerusalem chanced upon an unusual and ancient underground stalactite cave, Hadashot television news reported Friday.
The cave, some 280 meters (900 feet) below ground, is 14 meters (46 feet) long and was found earlier this week by Water Authority workers just outside (and under) the capital’s city limits.
Stalactites are formed by the slow dripping of water that deposits tiny amounts of material — in this case limestone and dolomite — in underground caves over many thousands of years, forming beautiful cones along the ceilings and floors of caves.
In the case of the newfound cave, the water dripping through it was clean and fresh, workers reported. The television report showed one worker drinking from a puddle on the floor.
The tunnel is due to be completed in 2020 and will supply water to Jerusalem and the Palestinian Authority for the next 50 years.
The cave was found while digging a 13.5 kilometer (8.4 mile) section of the tunnel between Ksalon, near Beit Shemesh, and Ein Kerem in the capital’s southwest.
“On Sunday, while digging, we found this large cavity,” the project supervisor told Hadashot news. “We knew we could not continue.”
Digging has been halted while the Nature and Parks Authority and other agencies document and explore the stalactite cave.
The cave will be permanently sealed in a month and a half and the digging will continue, officials said.