Watch NHK Documentary Season 20 Episode 9 Online

A tsunami is approaching from the sea. You start to run, but water rushes in from the river in the opposite direction. During the 2011 Great East Japan Earthquake, such "river tsunamis" charged in from the sea and barreled upstream, claiming many victims. A huge quake in Japan could cause a massive tsunami that would inundate urban areas. Squeezed between tall buildings, the water would rise, increasing its force and allowing no time to escape. With a heightened sense of crisis, officials are responding. This documentary uses computer graphics and eyewitness accounts to explore the dangers of river tsunamis and how people can stay safe.