One of the greatest photographic opportunities on this planet must be the Chicago Cloud Gate. It is a highly polished piece of stainless steel. Last summer I was over in Chicago on business and was able to go and see this installation on the north west corner of Millennium Park in downtown Chicago.
The thing I like about the Cloud Gate, or "Bean" (as the locals refer to it), is that no matter where you stand, there are the most amazing reflections of the sky, buildings, people, and and everything else around it.
If you are in Chicago, you would be a fool to miss the Bean out on your sight seeing.
Clicking on the photo will take you through to my Picasa album where you can see a map of where the photo was taken.