cindi preller: it shocked the world. it put tsunami into the global language. that was one of the first events where people had cameras to be able to capture what it looks like, what it sounds like, what the experience was. [man screaming] the indian ocean tsunami was so deadly because it was a surprise to many, many people. it was a huge wake up call for the need for advanced tsunami warning systems. it resulted in a significant improvement of global detection equipment and global coordination of tsunami warning systems. i don't think we'll ever see anything like that again of that magnitude of loss of life. stuart weinstein: the earliest recorded tsunami dates back to 2000 bc, and it occurred off the coast of syria. over the past 100 years, there have been five earthquakes with magnitudes of nine and above. all of them generated devastating tsunamis. tsunami waves travel very fast in the deep ocean, as fast as a jet plane at 500 miles an hour. they slow down as they reach shallow water to about 20 or 30 miles an hour. these are very long waves. if you're out