For centuries in the Near East archaeological evidence has been turning up of a major flood in the area's ancient history. In 1995, two marine biologists put forward evidence that showed that until almost 7500 years ago the Black Sea was a freshwater lake separated from the Mediterranean by a small strip of land where Istanbul now stands. Their theory suggested that around 5600 BC the Mediterranean broke through the land barrier and salt water poured through with a force 200 times that of Niagara Falls, inundating the Black Sea and raising its level by over 300 feet. In September 2000, marine archaeologist Robert Ballard discovered the wooden remains of houses 300 feet below the surface of the Black Sea, 12 miles north of the present-day Turkish coast. Building on this evidence Ian Wilson puts forward the hypothesis that this catastrophic inundation - the Biblical Flood - drowned tens of thousands of people and precipitated an exodus of people to Egypt and Mesopotamia, who formed the precursors of these great civilisations.