Check out the legacyphotoproject.com and click on the link for the worlds largest camera. Sometime this month a team of photographers are turning a former hanger on a decommisioned base into a giant pinhole camera. Be sure also to look at the galleries of images from the Legacy Project. Since 2002, they have been working on a long-term photographic study of a closed air base that is slated to be turned into a giant urban park in Southern California. PDN online has a story about it here.