Mt. Everest is the tallest mountain with the summit at 29,035 feet. It lies on the border between China (Tibet) and Nepal in the center of the Himalayan mountain range. Due to its size, it is buffeted by the jet stream with winds reaching speeds of over 100 mph, and this, combined with the avalanches, glaciers, ice-rivers and altitude, make this the most difficult of all the Seven Summits to climb.