Longest stay on Everest summit

Babu Chhiri Sherpa of Nepal completed a stay of 21 hours at the summit of Everest (8,848 m; 29,029 ft) without the use of bottled oxygen in May 1999. Most climbers stay for under an hour. Chhiri climbed Everest again just weeks later to become the first person to climb the mountain twice in the same season.