Tempera was used to paint frescos hundreds of years ago.

The exhibit has lots of recreated rooms and buildings, massive murals and movies.

Concerning murals, the picture above speaks for itself.

Other options to restore the frescoes would have required using chemicals to remove the unwanted layer or using physical means to scrape it off.

Few researchers, though, had given any serious thought to the relatively small and inconspicuous marks around the cave paintings.