This photo of London taken from the BT tower doesn't look very impressive but it's a screenshot from what is supposed to be the highest resolution panorama of a city ever taken. You can try zooming in on the image here. It is quite amazing that you appear to be able to read car number plates at a distance of several kilometres. This seemed to be better than predicted by Rayleigh so I thought I'd try some measurements. If you zoom in by that red arrow you'll find the London eye, down and to the left I found a sign by the river that I have reproduced here. The sign can't quite be resolved but that man's shirt can be. I estimate that it's possible to resolve objects about 2cm apart at this distance. I then used google maps to estimate the distance between BT tower and the London eye to be about 3km. The angle subtended by a 2cm object at a distance of 3km is 2/300000 rads = 6.7 x 10^-6 rads. According to the Rayleigh criteria the size of aperture that would be needed to resolve such an object would be given by θ= 1.2λ/a so a=1.2x600x10^-9/6.7x10^-6 which is about 10cm. So this is quite possible. The reason it appears so impressive is because the buildings in the panoramic view look much further way than they really are, pretty impressive all the same.

Here's a link to a website showing how it's done http://cutt.us/JKxk .Thanks Mazen for finding it.