The water from the melting glaciers began to rush toward the world's oceans, Ballard said, causing floods all around the world.
"The questions is, was there a mother of all floods," Ballard said.
According to a controversial theory proposed by two Columbia University scientists, there really was one in the Black Sea region. They believe that the now-salty Black Sea was once an isolated freshwater lake surrounded by farmland, until it was flooded by an enormous wall of water from the rising Mediterranean Sea. The force of the water was two hundred times that of Niagara Falls, sweeping away everything in its path.
Fascinated by the idea, Ballard and his team decided to investigate.
"We went in there to look for the flood," he said. "Not just a slow moving, advancing rise of sea level, but a really big flood that then stayed... The land that went under stayed under."
Four hundred feet below the surface, they unearthed an ancient shoreline, proof to Ballard that a catastrophic event did happen in the Black Sea. By carbon dating shells found along the shoreline, Ballard said he believes they have established a timeline for that catastrophic event, which he estimates happened around 5,000 BC. Some experts believe this was around the time when Noah's flood could have occurred.