One of the byproducts of the big real estate slowdown is that many homes and buildings for which the owners can no longer afford payment are being foreclosed upon. Subsequently, they are abandoned. There's probably no more visible display of the downturn than neighborhoods filled with empty buildings.
Mint's blog has done a great job documenting some of these locations in this post. Kind of eery, really. And for a more extensive treatment of the issue, this weekend's NYT magazine features an article on the abandoned homes problem in Cleveland by one of my favorite authors, Alex Kotlowitz.