The Dead Sea, also known as the Salt Sea in the Bible, is located at the southern end of the Jordan valley. The Dead Sea is 53 miles long (85 km), with an average breadth of 9 miles (14.5 km). The Dead Sea’s surface is at about 1,290 feet (393 meters) below sea level, and its greatest depth it is 1,300 feet (396 meters) below the Mediterranean. The shore of the dead sea is the lowest point of dry land on earth. It is fed mainly by the Jordan River and also by several smaller streams. The Dead Sea retains all of its salt and minerals because it has no outlet except by evaporation (which acts to concentrate it). The visible haziness is humidity caused by evaporation. The entire Jordan River Valley, through the Dead Sea, and continuing south through the Red Sea, is one major earthquake fault line.
At its northern shores are the cities of the plain: Sodom and Gomorrah, which were destroyed for their extreme wickedness. Zoar or Bela is located on the southern shore. See Genesis 14:2; 19:25; Deuteronomy 29:23. There are many Sink Holes (called slime pits in the Bible) around the Dead Sea. It was probably in a sink hole (slime pit) that the kings of Sodom and Gomorrah fell into as they fled after the Battle of Siddim, Genesis 14:1-10.
In New Testament times, Qumran (where the Dead Sea Scrolls were found) is near the northern shore. Masada is located on the western central shore. Bethabara, and Jericho are both a few miles from the northern shore.
The Dead Sea levels have been dropping because Israel, Jordan and Syria have been taking the water which would have naturally been feeding the Dead Sea. It is the same situation with the Great Salt Lake in Utah. There are several tourist beaches on both sides of the Dead Sea and it is fun to spend a few hours floating in the water (it is impossible to sink). Also mineral and salt extraction is carried out by several corporations.