"Sodom at the Dead Sea and Area" a Sedom Travel Page by Martin_S.

The Dead Sea is the lowest point on Earth at more than 400 meters below sea level. There is one entrance at the north where the Jordan River enters and there are 5 fresh water springs, among them Ein Gedi or Nahal David and Nahal Bokek. The high heat and lack of water entering it presents a perfect "cooking pot" for precipitation. The high rates causes what water left to be high in minerals and you can see on the edges of the sea the salt that has accumlated out.

The Malham Cave (or Ma'arat Malham in Hebrew) is on the shores of the Dead Sea and is the longest salt cave in the world. But be sure that if you can obtain permission to enter (it is closed most of the time) that you take plenty of water, it is a relatively hot environment when compared with most caves..