Located between Israel and Jordan, the Dead Sea sits at the lowest point on Earth. Its water is 10 times saltier than the ocean. Researchers have discovered the world’s longest salt cave in this salty, arid region.
Salt caves are unusual and rare geological features that “grow” in desert areas containing salt deposits. The Atacama Desert in Chile and Qeshm Island in Iran also have salt caves. Caves form when rainwater gushes over salt deposits. As it runs, the water dissolves the salt and seeps through crevices in the ground. The flowing saltwater forms channels. After the water dries, the channels remain, covered in salt.
At the Dead Sea’s southern tip lies Mount Sodom. Underneath the mountain is salt. A thin layer of hard rock protects Mount Sodom from completely washing away. Inside, Malham Cave—a natural labyrinth—twists and turns, stretching the length of the mountain. The combined length of the caverns totals about six miles.
Researchers have found at least 19 openings on the mountain’s slope. Seasonal floods percolated through Mount Sodom’s rock salt to form the giant cave. The cave’s main outlet is not far from a salt pillar called “Lot’s Wife.” It is named for the biblical character who disobeyed God by looking back at the destruction of Sodom and Gomorrah. (Genesis 19:26)
The Hebrew University of Jerusalem’s Cave Research Center (CRC) discovered Malham Cave in the 1980s. Since that time, yearly rainstorms have extended Mount Sodom’s maze of caves and tunnels. This year, the Hebrew University of Jerusalem and a collection of Israeli, Bulgarian, and other international cavers used lasers to measure the record-breaking main cave.
There’s no official record for the longest salt cave. Cave researchers usually just agree on a “winner.” Iran’s Namakdan Cave, which is about four miles long, had been known as the longest salt cave since 2006.
Efraim Cohen, a Hebrew University cave explorer, helped map Malham Cave by rappelling down into some of the cave’s salty shafts. “All the stalagmites and stalactites, their beauty, their color—they’re really white, they’re shining, they’re amazing,” he says.
Amos Frumkin is a Hebrew University geologist who has studied the cave for decades. He says, “If there is more water, more rainfall, the cave is enlarged,” Frumkin says. “This makes a huge difference in the morphology [form] of the cave.” So while scientists may have completed their study of Malham Cave for now, the world’s longest salt cave is still growing.