More than 3 million people visit Mount Rushmore National Memorial every year to see those famous chiseled presidential faces, but hardly any of them know that carved into the mountain, there's a secret chamber.
Mount Rushmore's sculptor, Gutzon Borglum, originally wanted Rushmore to feature the presidents from the waist up and to depict famous events in U.S. history. He also wanted a great "Hall of Records."
Borglum's idea was that thousands of years after civilization, the Hall of Records would be encased in the rock to tell the story of America to the future of mankind.
60 years after Borglum's death, the Hall of Records was never completed, but his vision was at least partially honored in 1998 when the vault was opened.
16 porcelain enamel plates with the Bill of Rights, the Constitution, the Declaration of Independence and some information on the presidents and Borglum himself were placed in the Hall of Records.
They were sealed in a teakwood box...
Placed in a titanium vault...
And buried under a 1,200-pound granite capstone slab.
The Hall of Records isn't open to the public, but next time you make a family trip to Mount Rushmore, you'll know it's right there.