It's over 62 years since Sir Edmund Hillary and Tenzing Norgay became the first climbers to climb Mt Everest.
But last year, for the first time in four decades, nobody scaled the world's highest peak.
Experienced climbers say climate change could make Everest more dangerous.
It's one of the world's greatest challenges for mountaineers, but it was virtually unconquerable last year after a major earthquake struck Nepal, causing an avalanche which killed 19 people at Base Camp.
"There was the potential for unstable parts of the mountain," says Guy Cotter from Adventure Consultants. "That was reason enough to go home from both sides. The Tibetan Mountaineering Association closed the north side of the mountain and sent all of the climbers home."
Those on the Nepal side also left, essentially closing down all climbing for the year.
At 29,029 feet, Everest is the world's tallest peak. It's been climbed by more than 4000 people and in 2013 alone, 658 reached the summit.
But 289 people have also died, including 16 Nepalese sherpas in 2014 following a major ice cliff avalanche in the Khumbu icefall.
While mountaineering's a big earner for Nepal, its government is introducing new regulations banning inexperienced climbers in an attempt to improve safety.
But some climbers believe climate change is also having an impact.
"No matter where we are in the world, especially if we're in the snow line or glaciers, certainly in my 30-year climbing career, it's obvious that there's glacial retreat everywhere we go," says English mountaineer Kenton Cool.
"There's the potential over time that glacial recession may cause the Khumbu icefall at the very bottom of Everest to become more impassable, more unstable potentially. It's a little hard to know, because we might end up with periods where access is actually improved for a period of time," says Mr Cotter.
He's expecting things to start getting back to normal this season, with plans to lead a Kiwi group to Everest in April.