Campeche, Mexico - The Ancient Maya City and Protected Tropical Forests of Calakmul in Mexico's Campeche state have been named "mixed natural and cultural" World Heritage Sites by UNESCO, the National Anthropology and History Institute, or INAH, said.

The World Heritage Committee added the two Mexican sites to the World Heritage List at its meeting in Doha, Qatar, last Saturday.

This is the first mixed site in Mexico added by the United Nations Educational, Scientific and Cultural Organization, or UNESCO, to its list, the INAH said.

"The city played a key role in the history of this region for more than 12 centuries and is characterized by well-preserved structures providing a vivid picture of life in an ancient Maya capital," UNESCO said in a statement posted on its web site.

The area added to the list is in the southern part of the Calakmul Biosphere Reserve and is considered the second-largest stretch of tropical forest in the Americas and the best protected, covering 1.78 million acres.

The Ancient Maya City of Calakmul was added to the World Heritage Sites list in 2002.