In order to ski down K2 in the Himalayas, at 28,251 feet elevation the second highest mountain in the world, you first have to climb it. On July 22, 2018 Polish climber Andrzej Bargiel reached the peak at about 1130am. By 730pm he had skied down its slopes to reach base camp. You can watch some of his journey below. I cannot imagine what his physical conditioning must be like.
K2 is a much more dangerous climb than Everest, with about 20% of climbers dying in the attempt. The only 25,000+ feet peak exceeding this death toll is Annapurna on which about 1 in 4 climbers die.