The Khumbu Icefall is the most dangerous part of any southern route on Everest. As the massive glacier of the Western Cwm tumbles over the steeper landscape below, tons of glacial ice shifts and crashes upon itself moving about three feet per day. More climbers have died here than on any other part of Everest. Every serac, like the huge one pictured here, will eventually collapse. Climbers hope it doesn't happen NOW.