1. The Rushmore cave
As well as vowing to etch the faces of George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln into the side of a South Dakota mountain (which some might say is ambitious enough), the sculptor behind the iconic Mount Rushmore National Monument, Gutzon Borglum, also had designs on carving illustrations of the most significant events in American history into the rock.
That proved an etch too far for Borglum, so instead he decided to excavate a cavity into the granite, behind Abraham Lincoln’s head, in which to store tablets chronicling the history of America. However, park authorities deem the unfinished cave too dangerous for tourists to visit, so it remains off limits.
2. The Statue of Liberty torch
Many tourists view New York from the crown of the Statue of Liberty, but there are better views from an observatory inside the torch, which is held high above the good lady’s head. So why can’t visitors access it?
Well, the torch has been off-limits since 1916, when German spies blew up a nearby munitions depot, which had been supplying the allies with weapons during WWI. The explosion, which had the force of an earthquake, caused significant damage to the torch. That damage has since been repaired, but the torch remains closed.