This video looks at the terrifying tsunami, a giant tidal wave that starts as an ordinary ripple in the ocean, and mysteriously enlarges to a wall of water measuring up to 100 feet high, and hundreds of miles long. The film features spectacular film footage of tidal waves, roaring towards shore at up to 500 miles an hour, destroying everything in their path. Interviews with scientists shed light on the causes of this unpredictable force of nature. Includes stories of survivors of the great waves in Japan and Peru.