The Dead Sea is a lake fed by the Jordan River and in ancient times it was known by many names such as the Salt Sea, the Eastern Sea, and the Sea of Sodom. Most of the names reference the fact that its salt and mineral content is 30% to 40%, while the oceans salt content is around 6%. Only about 2 inches of rain fall each year, but there are occasional and fierce thunderstorms. The sea is called "dead" because its high salinity means no macroscopic aquatic organisms such as fish or water plants can live in it, though minuscule quantities of bacteria and microbial fungi are present.
Situated on the heart of the Great Syrian-African rift valley that stretches throughout Israel and beyond, the Dead Sea is the lowest point on the earth, 1,320 feet below sea level and is flanked by the Judean Mountains on the west, the Hashemite Kingdom of Jordan and the Mountains of Moab on the east, the Jordan Valley and Sea of Galilee to the north and the Negev Desert as well as the Red Sea to the south.
The human history of the Dead Sea goes all the way back to remote antiquity. Just north of the Dead Sea is Jericho, the oldest continually occupied town in the world. The Greeks knew the Dead Sea as Lake Asphaltites, due to the naturally surfacing asphalt. Aristotle wrote about the remarkable waters. The Dead Sea is also the location of the Qumran community which produced the Dead Sea Scrolls. These ancient texts, preserved in sealed caves near the shore of the Dead Sea, provide remarkable insight on the religious and social beliefs of 1st-century Jews. King Herod the Great built and re-built several fortresses and palaces on the Western Bank of the Dead Sea. The most famous was Masada, where, in 66-70 AD, a small group of rebellious Jewish zealots held out against the might of the Roman Legion, and Machaerus where, it is believed John the Baptist had been imprisoned by Herod Antipas and met his death.