Evidence of farming settlements at Cuello in northern Belize dates to around 2000 BC. Over the following centuries, Mayan towns and villages encompassed Belize, Mexico’s Yucatán peninsula and much of Guatemala. The city of Caracol, near Belize’s border with Guatemala, is estimated to have spread over 140 sq. km, with some 180,000 residents at its height in the 7th century AD. However, the Mayan civilization declined rapidly after AD 900 for reasons that are still unclear. Construction of the great pyramid temples ceased, literacy was abandoned and subsistence farming returned.