Off-Limits: At Famous Landmarks

These legendary grottos in France’s Dordogne region are home to hundreds of cave paintings from the Paleolithic Age. Only a few years after Lascaux was opened to visitors, the art began to deteriorate; it was closed to the public in 1963, and a replica of the cave opened in the 1980s. You can check out reproductions of all those horses, bison and stag effigies on a tour of Lascaux II, but only very select scientists are allowed to enter the real deal.