Self-preservation is something that most humans take quite seriously, and that a few take to extremes. Faced with the real or imagined threat of attacks levied by nuclear, biological, and chemical weaponry, some people opt to head 25 feet underground, surrounded by concrete and complex air-filtration systems, surviving off rations and waiting, so to speak, for the end of the world.That's the subject of Richard Ross's Waiting for the End of the World, originally published by Princeton Architectural Press in 2004, for which Ross spent five years traveling over three continents, photographing the interiors of bomb shelters. "I'm a child of the late 1950s," he says. "I grew up in an era of duck-and-cover drills, where we always had to be acquainted with the idea of The Bomb." The exploration took Ross into a series of survivalist spaces, offering a visual index of the lengths to which people will go when they feel abused or threatened. "I ended up photographing an underground bomb shelter in Livermore, California, looking straight up [toward the entry from the surface], and the light was very divine and was essentially apocalyptic," he says. "Some of these people thought they were going to be the new inhabitants of the Garden of Eden. I can't believe that. But when you think back to the illogic of the Bush/Cheney administration, and the world around you is so devolved, the idea of going underground doesn't seem so crazy."Public shelter near Zurich, Switzerland. Major external air filters in communal shelter.The discs produced in this factory near Zurich are the tops of air filters.Doors of the public shelter near Zurich. Building code defines the specifications that are required of the shelters, though color schemes are optional. The entire population can be put underground in two hours. Bridges and tunnels throughout Switzerland are set with explosives to be blown in the face of an advancing enemy.The proud owner of a new single-family residence in Switzerland shows off his shelter. He is standing in front of his Andair-manufactured air filtration system with the escape hatch on the right.Charlie Hull Shelter, Emigrant, Montana. Bedroom. This 90-family "co-op shelter" was for members of the Elizabeth Clare Prophet Church, which predicted Doomsday on March 15, 1990. That day, the shelter was full; everyone emerged on March 16th and went home. The shelter has fallen out of favor and is maintained only by Charlie Hull and a few assistants.Charlie Hull Shelter. The chalkboard is there to make sure no one is accidentally locked in.Charlie Hull Shelter. Each of the 90 families for which the shelter was built chose their own spaces and equipped them with what they deemed necessary for their transition from a pre- to post-apocalypse. Some decorated their spaces with pink lace or hung up pictures.Living room, Charlie Hull Shelter.Conroe, Texas. This shelter was built during the 1980s by Ling Chieh "Louis" Kung, an oil tycoon nephew of Madame Chang Kai Shek.Conroe, Texas. Until recently, the structure was complete with conjugal rooms, a jail (pictured), body bags, operating rooms, armor, and steel doors.Operating room, Conroe, Texas.Philip Hoag's shelter in Emigrant, Montana, is located a few hours from Yellowstone National Park, and was built in 1989 by a group of about 130 people.Philip Hoag's shelter. The observation tower is equipped with tank periscopes to see above ground. Although many group shelters such as this one are outfitted with enough provisions to ensure survival for several years, they are not quite operational. It might take days to weeks to prepare these shelters for habitation in an emergency.Philip Hoag's shelter, Emigrant, Montana.Backyard entrance to a temporary shelter, Salt Lake City, Utah.Transverse tunnel, Salt Lake City, Utah.Storage shelves at a family shelter, Salt Lake City, Utah.Entrance to shelter, Saint Pete Sanpete Country, Utah. The entrance is on springs to withstand a nuclear blast; the shelter is 25 feet below ground and 50 feet long.Dining room, Saint Pete Sanpete Country, Utah. About 90 minutes from Salt Lake City, several families have larger scale, below ground shelters and above ground storage areas capable of feeding the members of the community for years.