Construction of Mount Rushmore Mount Rushmore for the sculpture, since it seemed to be the easiest and most stable of the cliffs to work on. Having decided on the location of the sculpture, Borglum decided to make the monument of four presidents of the United States. He chose the two most famous presidents in American history, George Washington and Abraham Lincoln. He chose Thomas Jefferson because Jefferson nearly doubled the size of the United States in the 1803 Louisiana Purchase (which included the land that became South Dakota). The last president Borglum chose was Theodore Roosevelt, suggested by President Calvin Coolidge (who insisted that
Mount Rushmore of Mount Rushmore", posing for photographs with thousands of tourists. He became one of the most photographed people in the world. The ongoing conservation of the site is overseen by the National Park Service. Physical efforts to conserve the monument have included replacement of the sealant applied originally by Gutzon Borglum, which had proved ineffective at providing water resistance. The components of Borglum's sealant included linseed oil, granite dust, and white lead, but a modern silicone replacement is now used, disguised with granite dust. In 1998, electronic monitoring devices were installed to track movement in the topology of the sculpture