Mount Rushmore still disputed on the basis of the 1868 Treaty of Fort Laramie (see section "Controversy" below). Among American settlers, the peak was known variously as Cougar Mountain, Sugarloaf Mountain, Slaughterhouse Mountain, and Keystone Cliffs. It was named Mount Rushmore during a prospecting expedition by Charles Rushmore, David Swanzey (husband of Carrie Ingalls), and Bill Challis. Historian Doane Robinson conceived the idea for Mount Rushmore in 1923 to promote tourism in South Dakota. In 1924, Robinson persuaded sculptor Gutzon Borglum to travel to the Black Hills region to ensure the carving could be accomplished. Borglum had been involved in sculpting the
Gutzon Borglum sculpted the memorial "Start Westward of the United States", which is located in Marietta, Ohio (1938). He built the statue of Daniel Butterfield at Sakura Park in Manhattan (1918). He created a memorial to Sacco and Vanzetti (1928), a plaster cast of which is now in the Boston Public Library. Another Borglum design is the North Carolina Monument on Seminary Ridge at the Gettysburg Battlefield in south-central Pennsylvania. The cast bronze sculpture depicts a wounded Confederate officer encouraging his men to push forward during Pickett's Charge. Borglum had also made arrangements for an airplane to fly over the monument during