Fireworks explode above the Mount Rushmore National Monument during an Independence Day event attended by the US president in Keystone, South Dakota, July 3, 2020. (Photo by SAUL LOEB / AFP ...

Construction of the Mount Rushmore monument began in 1927 and lasted until 1941. Borglum oversaw more than 400 workers with various specialties, including blacksmiths, drillers, and tramway operators.