Around 66 million years ago, a 15km-wide asteroid smashed into Mexico’s Yucatan Peninsula and is believed to have wiped out almost all the dinosaurs. The impact caused a megatsunami, liquified billions of tonnes of rock and created a 200km-wide crater in the Earth’s surface into which water seeped, creating thousands of sinkholes. Over millennia, some of these limestone sinkholes collapsed while others in the region eroded, forming vast networks of flooded cave systems.
Known as cenotes, these underground water reservoirs were more than just life-sustaining water sources for the Maya civilisation’s settlements; they were also believed to be sacred portals through which they could communicate with the gods of rain and creation. As such, the Maya routinely cast human sacrifices, gold plaques and bowls brimming with jade beads into the wells’ cavernous depths as offerings. Through these deep sinkholes, the deceased were thought to pass into the dark and treacherous underworld of Xibalba, where humans and deities were reborn.