There are know documented waves much bigger than that:

http://en.wikipedia.org/wiki/1958_Lituya_Bay_megatsunami

However if even a tiny wave like the one in that Photoshopped picture had hit a big city like the one in the picture, we'd all know.

It's one of the major risk for the U.S. east coast btw: there's a mountain in some Canary island (it's in non-continental Europe) that could see a gigantic landslide one of these days. If it happens, a 300 meters high wave would reach and destroy New-York in eight hours and pretty much the entire east coast of the U.S