The Dead Sea has attracted visitors from around the Mediterranean basin for thousands of years. In the Bible, it is a place of refuge for King David. 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. People also use the salt and the minerals from the Dead Sea to create cosmetics and herbal sachets.
The Dead Sea water has a density of 1.24 kg/litre, which makes swimming similar to floating.
The Dead Sea is an endorheic lake located in the Jordan Rift Valley, a geographic feature formed by the Dead Sea Transform (DST). This left lateral-moving transform fault lies along the tectonic plate boundary between the African Plate and the Arabian Plate. It runs between the East Anatolian Fault zone in Turkey and the northern end of the Red Sea Rift offshore of the southern tip of Sinai. It is here that the Upper Jordan River/Sea of Galilee/Lower Jordan River water system comes to an end.
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 Dead Sea is the saltiest water body and the lowest point on earth, swimmers can float effortlessly while receiving health benefits.
The Wadi Mujib valley, 420 m below the sea level in the southern of Jordan valley, is a biosphere reserve, with an area of 212 km2 (82 sq mi).
Rainfall is scarcely 100 mm (4 in) per year in the northern part of the Dead Sea and barely 50 mm (2 in) in the southern part. The Dead Sea zone's aridity is due to the rainshadow effect of the Judaean Mountains. The highlands east of the Dead Sea receive more rainfall than the Dead Sea itself.
To the west of the Dead Sea, the Judaean mountains rise less steeply and are much lower than the mountains to the east. Along the southwestern side of the lake is a 210 m (700 ft) tall halite formation called "Mount Sodom".
There are two contending hypotheses about the origin of the low elevation of the Dead Sea. The older hypothesis is that it 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.
Pebbles cemented with halite on the western shore of the Dead Sea near Ein Gedi.
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, 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 climate change. The Sedom Lagoon deposited beds of salt that eventually became 2.5 km (1.55 mi) thick.
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 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 obviously 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.
The first prehistoric lake to follow the Sedom Lagoon is named Lake Amora, followed by Lake Lisan and finally by the Dead Sea. The water levels and salinity of these lakes have either risen or fallen as an effect of the tectonic dropping of the valley bottom, and due to climate variation. As the climate became more arid, Lake Lisan finally shrank and became saltier, leaving the Dead Sea as its last remainder.
Halite deposits (and teepee structure) along the western Dead Sea coast.
In prehistoric times, great amounts of sediment collected on the floor of Lake Amora. The sediment was heavier than the salt deposits and squeezed the salt deposits upwards into what are now the Lisan Peninsula and Mount Sodom (on the southwest side of the lake). Geologists explain the effect in terms of a bucket of mud into which a large flat stone is placed, forcing the mud to creep up the sides of the bucket. When the floor of the Dead Sea dropped further due to tectonic forces, the salt mounts of Lisan and Mount Sodom stayed in place as high cliffs (see salt dome).
From 70,000 to 12,000 years ago, the lake's level was 100 m (330 ft) to 250 m (820 ft) higher than its current level. This lake, Lake Lisan, fluctuated dramatically, rising to its highest level around 26,000 years ago, indicating a very wet climate in the Near East. Around 10,000 years ago, the lake's level dropped dramatically, probably to even lower than today's. During the last several thousand years, the lake has fluctuated approximately 400 m (1,300 ft), with some significant drops and rises. Current theories as to the cause of this dramatic drop in levels rule out volcanic activity; therefore, it may have been a seismic event.
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