en.wikipedia.org/wiki/Mount_Rushmore

Mount Rushmore National Memorial is centered on a colossal sculpture carved into the granite face of Mount Rushmore (Lakota Tȟuŋkášila Šákpe, or Six Grandfathers) in the Black Hills in Keystone, South Dakota. Sculptor Gutzon Borglum created the sculpture's design and oversaw the project's execution from 1927 to 1941 with the help of his son, Lincoln Borglum. The sculpture features the 60-foot (18 m) heads of Presidents George Washington (1732–1799), Thomas Jefferson (1743–1826), Theodore Roosevelt (1858–1919) and Abraham Lincoln (1809–1865), as recommended by Borglum. The four presidents were chosen to represent the nation's birth, growth, development and preservation, respectively. The memorial park covers 1,278 acres (2.00 sq mi; 5.17 km2)[7] and the actual mountain has an elevation of 5,725 feet (1,745 m) above sea level.

Peter Norbeck, U.S. Senator from South Dakota, sponsored the project and secured federal funding. Construction began in 1927; the presidents' faces were completed between 1934 and 1939. After Gutzon Borglum died in March 1941, his son Lincoln took over as leader of the construction project. Each president was originally to be depicted from head to waist, but lack of funding forced construction to end on October 31, 1941

Hall of Records

A copy of one of the panels entombed in the Hall of Records Borglum originally envisioned a grand Hall of Records where America's greatest historical documents and artifacts could be protected and shown to tourists. He managed to start the project, but cut only 70 feet (21 m) into the rock before work stopped in 1939 to focus on the faces. In 1998, an effort to complete Borglum's vision resulted in a repository being constructed inside the mouth of the cave housing 16 enamel panels that contained biographical and historical information about Mount Rushmore as well as the texts of the documents Borglum wanted to preserve there. The vault consists of a teakwood box (housing the 16 panels) inside of a titanium vault placed in the ground with a granite capstone.