3. Lascaux Caves, France
Although this location has been given the privilege of being a World Heritage Site by the UNESCO, it has been inaccessible to the public since 2008. The caves are considered unique as they hold intricate and beautiful paintings of animals drawn in ancient times. An unfortunate fungal outbreak inside the caves compelled the French government to close the caves off permanently. Only historians and scientists are allowed inside the caves for short allotments of time for academic research.