Biblical city known for the legend of Sodom and Gomorrah. Both were cities in the valley of Siddim, near the dead sea. The biblical story tells of two sinful cities destroyed by a vengeful God. As the citizens were fleeing the city, God commanded them not to look back on the burning city. One woman ignored his command, and turned to find a giant mass of salt where the city once stood. Geologists have since then tried to explain the origins of this myth by postulating that an enormous earthquake simply swallowed the cities whole, around the time of 1900 B.C. The loose and waterlogged ground around the cities simply gave way under them. Geologists can explain this as well: a large tidal wave caused by the earthquake left a giant block of salt where the city once stood.
Sources: http://christiananswers.net/dictionary/sodom.html and http://www.archaeology.org/9607/newsbriefs/sodom.html