Factoid as to why Hillary and Norgay were the first to the top of Everest.

There had been a Swiss expedition in 1952 wherein a climber named Raymond Lambert and Tenzing Norgay reached the highest ever that far. It was well-equipped and had strong climbers.

Doctors, among others, examined the records of the climb. People in those days tended to keep very detailed records. The physicians concluded that the climbers did not drink enough water. Altitude does strange things to one's appetites.

The climbers on the following year's British expedition were ordered to drink more water. They did, about the only significant change from the earlier attempt, and the rest is history.