The mountain has had two names. Climbers in the 1800s called it Mount McKinley after a president. But the people who have lived in Alaska for thousands of years, the Koyukon Athabaskan people, have always called it Denali, which means 'the tall one'. In 2015, the country went back to using the older name.
Denali is so tall that it makes its own weather. The peak is often hidden in clouds even when the land below is sunny. People sometimes wait days at the bottom hoping to catch a glimpse of the top. When the clouds finally clear, the whole mountain seems to glow white above the forest.
Climbing Denali is harder than climbing many higher mountains. The air at the top is freezing cold all year round, and storms can move in within minutes. Most climbers train for years before they try. Even then, only about half of the people who set out actually reach the top.
The park around the mountain is enormous - bigger than the country of Belgium. Inside it live grizzly bears, moose, wolves, caribou and golden eagles. It is one of the few places on Earth where you can still see a wild landscape with almost no roads, no houses and no fences.