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 and secured federal funding; construction began in 1927, and the presidents' faces were completed between 1934 and 1939. Gutzon Borglum died in March 1941, and his son Lincoln took over as leader of the construction project. Each president was originally to be depicted from head to waist, but lack of funding forced construction to end on October 31, 1941. Mount Rushmore attracts more than two million visitors annually. Originally known to the Lakota Sioux as "The Six Grandfathers" (Tunkasila Sakpe) or "Cougar Mountain" (Igmu Tanka Paha), the mountain was renamed after Charles E. Rushmore, a prominent New York lawyer, during