Question

Why have the caves at Lascaux been closed to the public since 1963?

Answer 1

By 1955, carbon dioxide, heat, humidity, and other contaminants produced by 1,200 visitors per day had visibly damaged the paintings.

Answer 2

The caves at Lasacaux have been closed to the public since 1963 because of the air was let into them and the   Humidity resulted in the rapid deterioration of the paintings.