Located in Antarctica’s McMurdo’s Dry Valleys, the shallow Don Juan Pond is the world’s saltiest body of water. With a salt content that puts the Dead Sea to shame, it remains liquid even at -58 degrees Celsius (-50 Fahrenheit).

At four inches deep, Don Juan Pond looks more like a large puddle than an actual pond, but it has fascinated scientists for decades. A liquid puddle of this size in an alien-like environment where temperatures can drop to -50 degrees Fahrenheit was bound to draw attention at one point, and the tiny body of water has been buzzing with scientists since it was discovered in 1961. A quick analysis revealed its salt content to be around 40%; to put that into perspective the world’s oceans have a salinity of 3.5%, the Great Salt Lake varies between 5 and 27 percent, and the famous Dead Sea is 34% salt.