The Maya ruins of Tikal are hidden deep in the rainforests of Guatemala. From the air only a handful of temples and palaces peak through the canopy. The stone carvings are weather-beaten. Huge plazas are covered in moss and giant reservoirs are engulfed by jungle. The only inhabitants are wild animals and birds. However, 1200 years ago, Tikal was one of the major cities of the vast and magnificent Maya civilisation that stretched across much of what is now southern Mexico, Belize and Guatemala. Tikal was home to perhaps 100,000 people. Thatched farmsteads and fields would have stretched as far as the eye could see.
The Maya world had thrived for nearly 2000 years. Without the use of the cartwheel or metal tools, the Maya had built massive stone structures. They were accomplished scientists. They had tracked a solar year of 365 days and one of the few surviving ancient Maya books contains tables of eclipses. From observatories, like the one at Chichen Itza, they tracked the progress of the war star, Venus. They developed their own mathematics, using a base number of twenty, and even had a concept of zero. They also had their own system of writing. So stable and established were they, that they even had a word for a 400-year time period. Maya society was vibrant, but it could also be brutal. It was strictly hierarchical and deeply spiritual. Humans were sacrificed to appease the gods. The elite also tortured themselves. Male Maya rulers perforated the foreskins of their penises and the women their tongues, apparently in the hope of providing nourishment for the gods who required human blood.
However, in the ninth century, their world was turned upside down. Many of the great centres like Tikal were deserted. The sacred temples and palaces briefly became home to a few squatters, who left household rubbish in the once pristine buildings. When they too left, Tikal was abandoned forever - the Mayan civilization never recovered. Only a fraction of the Maya people survived to face the Spanish conquistadors in the 16th century. For decades, archaeologists have been searching for an explanation of the Maya collapse. Many theories have been put forward, ranging from warfare and invasion to migration, disease and over-farming. Many think the truth may lie with a combination of these and other factors.