Six photographers from the Legacy Project are spending tremendous amounts of time photographing the old El Toro Marine Corps Air Station in Orange County, California. One of their main projects was creating the world's largest camera obscuras, aka a "pinhole camera".
That consists of completely blocking all light from Building 115, a former jet hangar. A small hole cut in one end of the building displayed an image of the outside on a specially photo-sensitized fabric 80 feet away, which after 35 minutes developed into a picture. Latest news here; older details given here and here. The fabric measures somewhere around 28' by 108'. The non-profit org will be selling much smaller prints starting at $1600.
The image was developed by moving the fabric into an enormous, 1-foot-deep tray.
And, Guiness has created two new categories for this event: largest camera, and largest photograph.