Sculptor Gutzon Borglum was responsible for the monument to four presidents carved into Mount Rushmore in South Dakota. The project took 14 years to complete, but Borglum had another idea to ensure the history of his work: to carve an accessible museum into the rock, an archive to house all the information about the monument. He called it the Hall of Records.
After all, Borglum reasoned, what did we really know about Stonehenge? Or Egyptian pyramids? Civilizations could rise and fall while Rushmore stood, its origins getting more clouded with time.
To make sure people in the future knew the history of his project and the meaning behind it, Borglum announced an ambitious addition: a massive room situated just behind Abraham Lincoln’s hairline that would contain all the information anyone would ever need about the mountain. It would even house major historical artifacts like the Constitution and the Bill of Rights.
And there is a hall carved from the rock behind Mount Rushmore -but you can't go there. Read what happened to the Hall of Records at mental_floss.
(Image credit: National Park Service)