The "Tourist of Death"
I'm probably the last among this crowd to find this little link.
It is a site that was once dedicated to the visual hoax of the tourist atop the World Trade Center as a plane was headed towards it. Now it holds a few other major visual hoaxes, but I find the parodies of The Tourist of Death most interesting. I think it's wonderful how humor(and Photoshop) can diffuse a powerful image so quickly.