Gigapan.org has a snapshot feature for that. 26-gigapixel is bigger than most (all?) of what Gigapan has, but they have a bunch more. The Obama inauguration one[1] is probably their most famous.

I don't really ever get tired of being able to "enhance! enhance!"[2] an image.

1) http://gigapan.org/gigapans/15374/

2) http://www.youtube.com/watch?v=Vxq9yj2pVWk