South Dakota contains several sites that are administered by the National Park Service. Two national parks have been established in South Dakota, both located in the southwestern part of the state. Wind Cave National Park, established in 1903 in the Black Hills, contains an extensive cave network as well as a large herd of bison. Badlands National Park was created in 1978. The park features a highly eroded, brightly colored landscape surrounded by semi-arid grasslands. Mount Rushmore National Memorial in the Black Hills was established in 1925. The sculpture of four U.S. Presidents was carved into the mountainside by sculptor Gutzon Borglum. Other areas managed by the National Park Service include Jewel Cave National Monument near Custer, the Lewis and Clark National Historic Trail, the Minuteman Missile National Historic Site, which features a decommissioned nuclear missile silo and a separate missile control area located several miles away, and the Missouri National Recreational River. The Crazy Horse Memorial is a large mountainside sculpture near Mt. Rushmore that is being constructed with private funds.