The great Cro-Magnon paintings in the famous Lascaux Cave in France were done at least 15,000 years ago, but in the 15 years since the cave became a major tourist attraction, the paintings have been in greater danger than in all those previous centuries. In 1960 guards noticed that two green spots had formed on a wall, though fortunately a good way from the paintings. By 1962, there were 15 colonies of this green growth, thought to be an alga called Chlorella vulgaris that depended on the newly introduced light. When the number of colonies jumped to 93, with several of...
To continue reading:
or
Log-In
