Mount Rushmore is one of the United States’ most recognizable landmarks, but it contains a hidden secret: a 70-foot-long tunnel located behind Abraham Lincoln’s head. The tunnel was created as the entrance to a Hall of Records conceived by sculptor Gutzon Borglum. The idea was to build a chamber inside the monument that housed important documents such as the Constitution and Declaration of Independence, which would be accessible by an 800-foot granite stairway that stretched up the mountain from Borglum’s studio to the chamber. Work began on the Hall of Records in July 1938 as crews constructed the 70-foot tunnel. However, in 1939, Congress halted work on the chamber and instructed Borglum to focus on carving the Presidents’ heads instead. Borglum died two years later in 1941, effectively putting an end to the side project and leaving the Hall of Records unfinished.
Almost 60 years later, the Mount Rushmore National Memorial Society brought part of Borglum’s vision to life, installing a box at the chamber’s entrance containing 16 porcelain enamel panels. The panels explain the story of the United States and include biographies of the Presidents featured on Mount Rushmore. They were sealed beneath 1,200 pounds of granite capstone as an homage to Borglum’s initial vision.