Rushmore Cave into a rock known as limestone. The cave has a cornucopia of rooms including the Entrance Room, Post Office, Image Room, Big Room, Fairyland, Rope Room, Geode Room, The Rouge Room (Party Room), Arrowhead Room, and the Floral Room. The cave also includes boxwork and many dripstone formations including stalactites, stalagmites, columns, helictites and flowstone. Rushmore Cave Rushmore Cave is the closest show cave to Mount Rushmore National Memorial in the United States. It contains a wide variety of natural formations. It is the ninth longest cave in South Dakota. It measures a distance of . It was discovered in
Mount Rushmore center, finished in 1957. These structures were part of the Mission 66 effort to improve visitors' facilities at national parks and monuments across the country. On October 15, 1966, Mount Rushmore was listed on the National Register of Historic Places. A 500-word essay giving the history of the United States by Nebraska student William Andrew Burkett was selected as the college-age group winner in a 1934 competition, and that essay was placed on the Entablature on a bronze plate in 1973. In 1991, President George H. W. Bush officially dedicated Mount Rushmore. In a canyon behind the carved faces is