Helicopters (the Eurocopter AS350 Écureuil, specifically the B3 high-altitude version, the first helicopter to land on the summit of Mount Everest in 2005) are used to rescue climbers in difficulty in the Himalayas. Here's a montage of footage shot from them during their missions. Some of it is amazing.
I almost got vertigo watching some of the shots in full-screen mode. I imagine the pilots have to be amongst the best in the world at what they do, to manage a helicopter in the extremely thin air and high winds of those altitudes.