BASE jumpers just want to be free. How else can you explain it this extreme form of skydiving? BASE stands for the fixed objects people leap from: Buildings and antenna, spans such as bridges, and Earth, which usually means stunningly high cliffs.

The devil-may-care culture of these jumpers has pushed their extreme sport out of any place that imposes limits. They jump where they can, and in the United States, not very many places allow it. One go-to hub is Twin Falls, Idaho, where a bridge over the Snake River offers unfettered, year-round access to jumpers. But the sport is under scrutiny after at least five BASE jumpers have died this year, including 73-year-old James E. Hickey, who set his parachute on fire as he jumped off the bridge in a stunt this month. His second chute didn't deploy.

Also this month, Carla Jean Segil, 26, was left dangling 500 feet above the Snake River after a gust of wind blew her parachute into the bridge. She hung in the air for 40 minutes until a Twin Falls rescue crew pulled her up through a manhole.