This is cool.

I used to have a poster on my office wall called The Earth At Night. It was a composite of night-time satellite photographs of the entire globe, seamlessly joined. I used to love staring at it, picking out places I'd been, or places I wanted to go to, marvelling at the spread (or lack thereof) of development, wondering about the darkness of central Africa and the Amazon basin.

If you get off on that kind of imagery, check out this link.