#9. DENALI, Alaska (20,320 ft.)
The mountain is prone to earthquakes. And the combination of high altitude and extreme latitude also means altitude sickness kicks in much faster. (At the equator, a peak this size would have about half as much oxygen at the summit than at sea level; because of the latitude, the percentage on Denali is far lower.)
#10. Mt. Fuji, Japan (12,388 ft.)
Sometimes you don’t have to be a tall mountain to be a lethal one. Take Mt. Fuji, for example. At its base sits the Sea of Trees, a large expanse of cedar, pine, and boxwood trees that was the only area not overrun by lava and ash during a massive eruption in 1707. This forest, know as Aokigahara, has attained cult status among Japanese as the perfect place to die. Rumors about the woods abound: locals speak of magnetic fields that disorient search and rescue operations; the forest’s population is said to consist of snakes, wild dogs, and the occasional demon.