Extreme athlete Dean Potter, renowned for his daring and sometimes rogue climbs and BASE jumps, was one of two men killed while attempting a wingsuit flight in Yosemite National Park, a park spokesman said Sunday. Someone called for help late Saturday after losing contact with Potter, 43, and his climbing partner, Graham Hunt, 29. They had jumped from a 7,500-foot promontory called Taft Point, park ranger Scott Gediman said. He said a search-and-rescue team looked for the men overnight but couldn't find them. On Sunday morning, a helicopter crew spotted their bodies in Yosemite Valley. The men wore wingsuits — skin-tight suits with batwing sleeves and a flap between their legs — to help them glide. However, parachutes designed to slow their descent had not been deployed, Gediman said. BASE stands for buildings, antennas, spans (such as bridges), and Earth (such as cliffs and mountaintops) that jumpers can parachute from. The sport is illegal in all national parks, and it was possible the men jumped at dusk or at night to avoid being caught by park rangers.