http://labs.live.com/photosynth/whatis/default.html
Photosynth is a new image processing technology from Microsoft that takes a collection of images (say, of a famous location), analyzes them for similarities & rebuilds the location in virtual space for the user to fly though, zooming in on details, panning around like a 3D Hockney piece
Downloadable videos of how it works here:
http://labs.live.com/photosynth/videodemo.html
(Shamelessly swiped from www.metafilter.com by a lister)