I have just seen the Yahoo News video of the Japanese tsunami. It is the most horrific, inexorable destruction I've ever watched. It is something you need to see but won't enjoy.
To me it's worse than a nuclear explosion because it is slow enough for the human mind to grasp. You see a town being ground up in almost slow motion, buildings floating inland only to ram into each other, then collapse and become watery debris that moves like lava.
Early on you see a car unknowingly driving toward inevitable destruction. Later, in a field you see people running away too slowly, trying to save something, maybe a child or a prized possession.
I'll be surprised if this video doesn't haunt you.