The video: In the days following Japan's catastrophic earthquake and tsunami, YouTube lit up with footage shot by witnesses to the disaster. But perhaps the most terrifying video took more than two weeks to emerge. In a five-minute clip (watch it below), a camera-equipped bystander in the northeast town of Kesennuma takes refuge on a tall building's roof as frighteningly powerful waves roll across the town's seaside road, sweeping up cars as if they were children's toys. The water rapidly builds, before quickly overwhelming most of Kesennuma's small buildings. At the 2:54 mark, a stranded boater can be seen struggling unsuccessfully to beat back the current; in a matter of 180 seconds, most of the town has been consumed by an unstoppable torrent of black water.

The reaction: This might be the "most insane" footage to date, says AllahPundit at Hot Air. "By the end of the clip, if not for that lone building on the right edge of the frame, you wouldn’t know civilization had been there." Truly, footage like this makes the terrible truth of what happened in Japan come to life, says Alex Alvarez at Mediaite. Actually witnessing such destruction "helps put things in perspective, and brings a dose of reality where words and still images cannot." Watch the incredible footage: