El Capitan
From Memory Alpha, the free Star Trek reference
El Capitan was a geological formation in the Yosemite National Park's High Sierras on Earth. Not precisely a mountain, it was actually a giant rock popular with rock climbers.
As a challenge to himself in 2287, James T. Kirk attempted free climbing El Capitan solo, without any safety equipment; an attempt which nearly resulted in his death. Fortunately Spock saved Kirk's life with the help of his jet boots. (Star Trek V: The Final Frontier)
