The Dead Sea is the lowest point on Earth at about 1,400 feet below sea level.
Its waters are 10 times saltier than regular sea water. While full of therapeutic minerals, the water is toxic to ingest.
That didn't stop 28 swimmers from swimming nine miles across it, from Jordan to Israel, in the first-ever Dead Sea Swim.
Sponsored by EcoPeace Middle East, the event sought to raise awareness of its receding waters due to Israeli and Jordanian mining.
next slide will load in 15 secondsSkip AdSkip AdIn the past 30 years, the Dead Sea has dropped by 80 feet.
The salty water is so buoyant that swimmers can't sink.
Even the tiniest drop of water in the eyes burns like crazy.
Still, swimmers from South Africa, Kenya, New Zealand, the UK, and Israel persevered.
"The swim took incredible teamwork," Kim Chambers, an open-water swimmer from New Zealand, told Reuters.
next slide will load in 15 secondsSkip AdSkip Ad"We had unprecedented diplomatic support from Israel and Jordan to make it happen."
"That's what's needed to bring attention to an issue that needs attention right now."
After completing their swim, swimmers washed the irritating, salty water off of their skin.
"We see the life-threatening challenge of the swim as parallel to the challenges facing the Dead Sea," Gidon Bromberg, Israeli director of EcoPeace Middle East, said in a statement.