An oxygen mask is covered with sweat at the Columbia Center during the Scott Firefighter Stairclimb in Seattle on Sunday. About 1,550 firefighters from the U.S., Canada and Germany participated in the climb, which requires participants to scale 69 flights of stairs and 1,311 steps equaling 788 feet of elevation. The annual climb is the largest in the world. Photo: LINDSEY WASSON / SEATTLEPI.COM