Mount Rushmore National Memorial is a sculpture carved into the side of Mount Rushmore in the Black Hills of South Dakota, USA.
Local historian Doane Robinson came up with the idea for Mount Rushmore in 1923 in order to promote tourism in South Dakota.
Gutzon Borglum, a famous Dutch-American sculptor, was selected for the Mount Rushmore project. At his death in March 1941 his son, Lincoln Borglum, continued the work and it was completed later that year.
The Memorial depicts 4 American Presidents, George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln who represent the first 130 years of American history.
Carving of Mount Rushmore started on October 4, 1927, and finished 14 years later on October 31, 1941.
Over 400 workers helped to sculpt Mount Rushmore climbing 506 steps to its top each day and amazingly there were no fatalities.
Originally the plan was to carve the sculpture into nearby granite pillars known as the Needles. However, these were deemed to thin and eroded to support the sculpture.
Mount Rushmore standing 5,725 ft (1,745 m) above sea level was chosen due to its grand location, quality granite and because it faced southeast so enjoyed maximum exposure to the sun which helped maximise working hours.
Initially, it was planned for the figures to be carved from head to waist, but a shortage in funding didn't allow for this.
The whole project cost US $989,992.32.
Dynamite was used to carve Mount Rushmore followed by a process called 'honeycombing'. About 450,000 tons (over 800 million pounds) of stone was removed of the side of the mountain during construction.
To start with Thomas Jefferson was carved to the right of George Washington. However, after 18 months it was decided that this wasn't working so Jefferson's face was dynamited off and his face carved on the opposite side.
Maintenance of the Rushmore memorial requires annual monitoring, cleaning and sealing of cracks, work that is undertaken by trained mountain climbers.
The monument is 60 foot (18 m) high. Each of the President's heads are the height of a six-story building, their eyes are 11 ft across, their noses are 20 ft long and their mouths 18 ft wide.
A cave called the 'Hall of Records' sits behind the monument and contains a vault of 16 porcelain enamel panels with text of the Declaration of Independence, the Constitution, biographies of the 4 presidents and Borglum, and history of the U.S.