You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: WORLD RECORDS 
Clue: In May 2000 Babu Chhiri, a Sherpa, set a record doing the last portion of this in about 16 hours
climbing mount everest