Named from the Athabaskan Indian word for "The High One," Denali National Park is home to the highest point in North America, reaching 20,320 feet above sea level. 1896, however, the region was still marked as "unexplored" on official maps and the mountain was renamed Mount McKinley, after the presidential candidate. Charles Sheldon, a naturalist, was the driving force behind turning the region into a national park to preserve the wildlife, especially the Dall sheep. The park was instated in 1917 but was named McKinley National Park rather than Denali. Only the first 15 miles of the road are available to private vehicles, after which visitors can access the interior of the park through buses. There are also several fully-narrated tours of the park, the most popular of which is the Tundra Wilderness Tour.