A pernicious white fungus has spread "like snow" in the caves of Lascaux in France where the fabulous rock art has been described as the "Sistine Chapel of prehistory".
The fungus is believed to have been introduced after contractors began to install a new air conditioning system that was meant to preserve the precious 17,000-year-old cave paintings from the heat and humidity generated by their many visitors.
The historical importance of Lascaux is immeasurable and any damage to its art would have serious repercussions given the cave's status as an evolutionary icon for the development of human art and consciousness.
Close it up and let it be.
After getting rid of the fungus.