Border Patrol agents call it el Tour de Los Estados Unidos. The winners of this Tour gain illegal entry into the US from Mexico on bicycles they use to cross the border.

The rundown bikes cost $20 to $25 each. They run the gamut from mountain bikes to Chinese models with wing handlebars. The reflectors are removed; one bike was painted camouflage green, while others are spray painted black.

The immigrants ride the bikes at night on hiking trails or unused desert roads. The Organ Pipe Cactus National Monument, right, is a favorite route.

"Usually you hear what sounds like off-road truck tires coming toward you down the road 'cuz there's so many of them" ...   more »