Mount Rainier is the 5th highest mountain in the contiguous United States. Mount Whitney is the highest.
From this Forbes article on Everest deaths: one in ten mountain climbers die trying to summit, and those who successfully summit have a one in twenty chance of dying on the way down.
Humans living in higher altitudes acclimatize by increasing the number of red blood cells, thereby increasing the capacity for oxygen and carbon dioxide movement within the body.
Fun facts were inspired by a recent Mount Adams climb.