The Dead Sea (Deepest Hypersaline Lake), Between Israel and Jordan

The Dead Sea also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Bank to the west. It lies in the Jordan Rift Valley, and its main tributary is the Jordan River.

The lake's surface is 430.5 meters (1,412 ft) below sea level, making its shores the lowest land-based elevation on Earth. It is 304 m (997 ft) deep, the deepest hyper saline lake in the world. With a salinity of 342 g/kg, or 34.2% (in 2011), it is one of the world's saltiest bodies of water  9.6 times as salty as the ocean  and has a density of 1.24 kg/litre, which makes swimming similar to floating.This salinity makes for a harsh environment in which plants and animals cannot flourish, hence its name. The Dead Sea's main, northern basin is 50 kilometres (31 mi) long and 15 kilometres (9 mi) wide at its widest point.

The Dead Sea has attracted visitors from around the Mediterranean Basin for thousands of years. It was one of the world's first health resorts (for Herod the Great), and it has been the supplier of a wide variety of products, from asphalt for Egyptian mummification to potash for fertilizers. Today, tourists visit the sea on its Israeli, Jordanian and West Bank coastlines. The Palestinian tourism industry has been met with setbacks in developing along the West Bank coast.

The Dead Sea is receding at a swift rate; its surface area today is 605 km2 (234 sq mi), having been 1,050 km2 (410 sq mi) in 1930. The recession of the Dead Sea has begun causing problems, and multiple canal and pipeline proposals, such as the scrapped Red Sea–Dead Sea Water Conveyance project, have been made to reduce its recession. 

The Dead Sea is located at the lowest point on earth, which is thought to be the result of volcanic processes leading to a continuous dropping of land. It is one of the four saltiest bodies of water in the world. These special conditions are an outcome of its extreme geomorphological structure alongside a harsh desert climate. These create constant dramatic changes that form a landscape that is different from any other in the world. Also, the unique mineral content of the air, land, and water in the area is globally renowned for its therapeutic qualities, as is evident in that it has been a health resort for thousands of years.

The Jordan River is the only major water source flowing into the Dead Sea, although there are small perennial springs under and around the Dead Sea, forming pools and quicksand pits along the edges.  There are no outlet streams.

The Mujib River, biblical Arnon, is one of the larger water sources of the Dead Sea other than the Jordan. The Wadi Mujib valley, 420 m below the sea level in the southern part of the Jordan valley, is a biosphere reserve, with an area of 212 km2 (82 sq mi).  Other more substantial sources are Wadi Darajeh (Arabic)/Nahal Dragot (Hebrew), and Nahal Arugot that ends at Ein Gedi. Wadi Hasa is another wadi flowing into the Dead Sea.

There are two contending hypotheses about the origin of the low elevation of the Dead Sea. The older hypothesis is that the Dead Sea lies in a true rift zone, an extension of the Red Sea Rift, or even of the Great Rift Valley of eastern Africa. A more recent hypothesis is that the Dead Sea basin is a consequence of a "step-over" discontinuity along the Dead Sea Transform, creating an extension of the crust with consequent subsidence.

During the late Pliocene-early Pleistocene, around 3.7 million years ago, what is now the valley of the Jordan River, Dead Sea, and the northern Wadi Arabah was repeatedly inundated by waters from the Mediterranean Sea. The waters formed in a narrow, crooked bay that is called by geologists the Sedom Lagoon, which was connected to the sea through what is now the Jezreel Valley. The floods of the valley came and went depending on long-scale changes in the tectonic and climatic conditions.

The Sedom Lagoon extended at its maximum from the Sea of Galilee in the north to somewhere around 50 km (30 mi) south of the current southern end of the Dead Sea, and the subsequent lakes never surpassed this expanse. The Hula Depression was never part of any of these water bodies due to its higher elevation and the high threshold of the Korazim block separating it from the Sea of Galilee basin.

Approximately two million years ago, the land between the Rift Valley and the Mediterranean Sea rose to such an extent that the ocean could no longer flood the area. Thus, the long lagoon became a landlocked lake.

The Dead Sea area has become a location for health research and potential treatment for several reasons. The mineral content of the water, the low content of pollens and other allergens in the atmosphere, the reduced ultraviolet component of solar radiation, and the higher atmospheric pressure at this great depth each may have specific health effects. For example, persons experiencing reduced respiratory function from diseases such as cystic fibrosis seem to benefit from the increased atmospheric pressure.

The region's climate and low elevation have made it a popular center for assessment of putative therapies:

Climatotherapy: Treatment which exploits local climatic features such as temperature, humidity, sunshine, barometric pressure and special atmospheric constituents.

Heliotherapy: Treatment that exploits the biological effects of the sun's radiation

Thalassotherapy: Treatment that exploits bathing in Dead Sea water

Climatotherapy at the Dead Sea may be a therapy for psoriasis by sunbathing for long periods in the area due to its position below sea level and subsequent result that UV rays are partially blocked by the increased thickness of the atmosphere over the Dead Sea.

Rhinosinusitis patients receiving Dead Sea saline nasal irrigation exhibited improved symptom relief compared to standard hypertonic saline spray in one study.

Dead Sea mud pack therapy has been suggested to temporarily relieve pain in patients with osteoarthritis of the knees. According to researchers of the Ben Gurion University of the Negev, treatment with mineral-rich mud compresses can be used to augment conventional medical therapy.

The minerals and salts exclusive to the Dead Sea have been luring visitors for thousands of years, making it the world’s first health resort, dating back to the time of Herod. The high concentration of antiseptic minerals in the mud and salt of the Dead Sea makes it especially beneficial for skin diseases such as psoriasis and vitiligo. Covering the body in mud extracted from the Dead Sea helps the minerals become absorbed into the skin.

There are quite a few mentions of the Dead Sea in the Bible, and it has long been associated with mysticism, wonderment, and religious significance. It has been referenced often to describe the borders of Israel but is also known in its own right. One famous reference is the story of Lot’s wife, which is set in nearby Sodom. The slopes of Mount Sodom are located in the southeast corner of the Dead Sea, and they feature salt formations that look like pillars which are traditionally referred to as Lot’s wife.

Another famous mention is the Dead Sea prophecy, in which the prophet Ezekiel foresees a time when the Dead Sea would be transformed from saline waters that cannot host life, into fresh waters teeming with sea life.

The water level of the Dead Sea has been receding gradually, at an average annual rate of about 110 cm. This causes some concern about whether the Dead Sea is drying up. The natural recession is caused mainly by evaporation under the harsh desert sun, but also because water is no longer being pumped into the Dead Sea from former sources like the Jordan River

One of the main must-do activities on all tourists’ lists is floating in the Dead Sea. Because of the high concentration of salt, the water is much denser than plain fresh water, meaning that our body weight is lighter which causes us to float.