Celebrations are underway in Nepal to mark the 60th anniversary of the first successful ascent of Mount Everest.
Four days of ceremonies, dubbed the Everest Diamond Jubilee, conclude on Wednesday night with a gala at the former royal palace in the capital Kathmandu in honour of the first successful climbers, New Zealander Sir Edmund Hillary and Tenzing Norgay.
The British expedition in 1953 changed mountaineering forever and turned Sir Edmund and Tenzing Norgay into household names and heroes in many parts of the world.
"Hillary and Tenzing were rock stars of the 1950s and into the 1960s," Sir Edmund's son Peter told AFP.
"The biggest thing about 1953 is that they were going into the unknown. People didn't know what was up there, they didn't know whether or not you could remain conscious, they didn't know whether they could climb that final summit knife-edged ridge and get up what is now called the Hillary Steps."
A host of famous mountaineering figures will be at the gala on Wednesday night, including Everest legend Reinhold Messner of Italy, as well as Kancha Sherpa, the last remaining member of the 1953 expedition.
Mr Kancha, who is 81, remembers the expedition as an arduous but ultimately joyous affair, although he regrets that the glory is not more equally shared among the team.
"Everyone knew Tenzing and Hillary climbed Everest, but nobody knows how hard we worked along the way.
"One thousand two hundred coolies (porters) were gathered together at Bhaktapur near Kathmandu ... Everyone walked from there because there weren't any roads, no motor vehicles, no planes. It took us 16 days to reach Namche," which today is the start of the Everest route.
"Then, it was very difficult because there were no ladders. It feels like a dream now. But we struggled a lot. I was frightened when I came across Khumbu Icefall. That was the first big barrier."
Peter Hillary and Tenzing Norgay's son Jamling, both now mountaineers, will join the Queen at a an event at the Royal Geographical Society in London on Wednesday.
Mr Hillary, like many others in the mountaineering community is now concerned about the commercialisation of Everest which is more popular than ever, but is also increasingly overcrowded and filthy.
This season alone 540 people reached the summit, including an octogenarian, the first female amputee, the first women from Saudi Arabia and Pakistan, and the first armless man.