A scary series of pictures of what could have been a near mid air collision over London, although there's no telling how close those planes really are. But even if there's a lot of foreshortening going on, I doubt they're the 3 nautical miles apart that they're supposed to be.
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I bet at least 2 people had to change their underwear after this.
Optical illusion according to airport authorities.
http://www.snopes.com/photos/airplane/closedhl.asp
Good discussion of the real separation distance here:
http://www.airliners.net/discussions/general_aviation/read.main/2577187/