The saltiest a body of water in the world is so salty that it does not freeze at -58 degrees (2 photos + 1 video)
Located in the Dry Valleys of Antarctica, the shallow Don Juan Pond is the saltiest body of water on Earth. It has a salt content greater than the Dead Sea, and it remains liquid even at temperatures as low as -58 degrees Celsius.
At just 10 centimeters deep, Don Juan Pond is more of a puddle than a true lake, but it has fascinated scientists for over 60 years. A liquid pool of that size in an alien environment where temperatures can drop to -58 degrees Celsius was too big to ignore, and the little pond has continued to fascinate researchers since its discovery in 1961. A quick analysis showed that its salt content was around 40%; For comparison, the world's oceans have a salinity of 3.5%, the Great Salt Lake has a salinity of 5 to 27%, and the famous Dead Sea has 34% salt. 
Photo: By Dturme – Own work, CC BY-SA 4.0
The saltiest body of water on the planet is hidden in a valley in one of the driest places on Earth, where it never rains and rarely snows. Few other bodies of water in the area are covered by several meters of solid ice, but the waters of Don Juan Pond, rich in calcium chloride, very rarely freeze. Salt particles lower the freezing point of water by moving between molecules and preventing the formation of a crystalline lattice of ice.
One of the biggest mysteries of Don Juan Pond is its origin. For decades, scientists believed that the pool of water was constantly being fed by underground water rising to the surface. However, about a decade ago, geologists Jay Dixon and James Head from Brown University determined that the salt water most likely came from the atmosphere. By setting up cameras, they were able to show that salts in the soil of the McMurdo Dry Valleys absorb moisture from the air through a process called deliquiescence. These salts, saturated with moisture, then flow down to Don Juan Pond, often mixing with meltwater from snow and ice. 
Another interesting feature of Don Juan Pond is the possibility of microscopic life forms in its extremely salty waters. The possibility of life existing in such extreme conditions may indicate that life exists or has existed on planets like Mars.
"There is definitely biology in the vicinity of the pond and some evidence of biological activity in the pond itself, but that activity can be explained by abiotic processes," Jay Dixon explained. "Mars has a lot of salt, and there was once a lot of water there."
