The entrance to the Lascaux Cave was discovered by chance in 1940 by 18-year-old Marcel Ravidat, an apprentice garage mechanic. Ravidat returned later with three friends, entering the cave through a 15 metre deep shaft that they believed might be a legendary secret passage leading to nearby Lascaux Manor.
On entering the cave, the teenagers discovered that the walls were covered with prehistoric paintings, mostly depictions of humans, animals and abstract signs. In total, over 600 paintings cover the interior walls and ceilings of the cave, which opened to the public for a brief period before closing in 1963, when carbon dioxide from visitors’ breathe was found to be damaging the paintings. In 1979, Lascaux was inducted into the UNESCO World Heritage Sites list but, with authorities still battling the growth of moulds and fungi in the cave, it is doubtful that it will reopen to the public any time soon.
Lascaux horse (dated c.17000 - 15000 BCE) via Ancient History Encyclopaedia online