<Table> <Tr> <Td> </Td> <Td> This article's lead section does not adequately summarize key points of its contents . Please consider expanding the lead to provide an accessible overview of all important aspects of the article . Please discuss this issue on the article's talk page . (August 2017) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article's lead section does not adequately summarize key points of its contents . Please consider expanding the lead to provide an accessible overview of all important aspects of the article . Please discuss this issue on the article's talk page . (August 2017) </Td> </Tr> <P> The construction of Mount Rushmore National Memorial took 14 years, from 1927 to 1941 . </P> <P> Doane Robinson of the South Dakota Historical Society wanted a monument to be built in South Dakota in order to help the economy of the state by attracting tourism . In 1923, he proposed that this monument should be built from the granite cliffs in the Black Hills of South Dakota . Senator Peter Norbeck of South Dakota approved the proposal, and federal funding helped the project . Robinson asked architect and sculptor Gutzon Borglum to sculpt and design the monument . Borglum decided to use Mount Rushmore for the sculpture, since it seemed to be the easiest and most stable of the cliffs to work on . </P>

When did they start working on mount rushmore