Mount Rushmore National Memorial, located in the Black Hills in Keystone, South Dakota, was designed by sculpture Gutzon Borglum and executed from 1927 to 1941. Four hundred workers carved the sculpture into granite using dynamite, followed by the process of “honeycombing”, when holes are drilled close together, allowing small pieces of granite to be removed by hand. In total, about 450,000 short tons of rock were blasted off the mountainside.
The 60-foot heads of Presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln were chosen to represent the nation’s birth, growth, development, and preservation.