NAT GEO: Aztec, Maya Were Rubber-Making Masters?

"Ancient civilizations in much of Mexico and Central America were making different grades of rubber 3,000 years before Charles Goodyear "stabilized" the stuff in the mid-19th century, new research suggests."

URL: http://news.nationalgeographic.com/news/2010/06/100628-science-ancient-maya-aztec-rubber-balls-beheaded/