Gigapan has huge panoramic images of all sorts of stuff: the space shuttle, cities, landscapes, maps, machines, insects and who knows what else.
The images are stitched together form a huge number (thousands in many cases) and the clarity even when you zoom in is amazing. Something to play with and something useful for research, if you want to get a good look at a place you've never been.
Via an old article at Not Exactly Rocket Science. If you're not already reading that blog, you should.