Click Here to Read: In a chamber at the end of a tunnel in Mexico sealed for nearly 1,800 years, archeologists make a toxic discovery by Sarah Kaplan in the Washington Post on April 27, 2015.
An undated graphic shows the tunnel that may lead to a royal tomb discovered underneath the Quetzalcoatl temple in the ancient city of Teotihuacan in this October 29, 2014 handout file picture. National Institute of Anthropology and History