The Chicago skyline at night, photographed from the Planetarium across the frozen surface of Lake Michigan. By taking the photo on a weeknight in winter it's possible to get adequate darkness while there are still workers in their lit-up offices. This is one of the photographs that's been stolen from me most often - I keep having to request web hosts to remove this picture from people's websites, and I've even had to use lawyers' letters to squeeze money out of a couple of people who were using it commercially.