A re-nomination and extension of the existing almost 7500 acres cultural World Heritage Calakmul Biosphere Reserve, UNESCO has recently enlarged it to 1.78 million acres designated as mixed natural and cultural property, the first one in the country. Located in the southern portion of the Yucatan Peninsula, the extension includes the remains of Calakmul, the important municipality that played a key role in the history of the Maya for more than 12 centuries. Characterized by well-preserved structures providing a vivid picture of life in an ancient Maya city, texts found here show that it was the royal capital of the Kaan, or Snake, family, the polity that challenged Tikal for supremacy.