The potential of Microsoft Live Labs Photosysnth is mind boggling.
From Live Labs:
Photosynth takes a large collection of photos of a place or object, analyzes them for similarities, and displays them in a reconstructed 3-Dimensional space. With Photosynth you can:
walk or fly through a scene to see photos from any angle;
seamlessly zoom in or out of a photograph even if it’s gigapixels in size;
see where pictures were taken in relation to one another;
find similar photos to the one you’re currently viewing;
explore a custom tour or see where you’ve been; or
send a collection to a friend.
Check out the video tour that shows the basic concept.
Can you just imagine merging this with something like Google Earth?