Rushmore Cave 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 1876 when a log flume that supplied water to mining operations in town of Hayward broke and spilled onto the side of the hill. As the water flowed down the hill it started flowing into a small hole in the hillside. The local miners who went up to fix the flume noticed this abnormality and
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