Some 65 million years ago the Chicxulub asteroid struck the Yucatán Peninsula – near the town of the same name – an event that is considered to have contributed to the extinction of the dinosaurs. The strike also caused large sections of the region’s limestone bedrock to collapse, in turn forming thousands of cenotes (sinkholes).
The region’s network of cenotes – which are generally filled with fresh water – was crucial for the Maya civilization that dominated the Yucatán Peninsula before the arrival of the Spanish conquistadors in the 1500s. These flooded subterranean chambers were vital sources of potable water in an area short on rivers and lakes, and towns, villages and ceremonial sites often sprung up around them. They were also considered sacred gateways to the Maya underworld, known as Xibalba (“the place of fear”). At Cenote Sagrado at Chichén Itzá (see p.752), for example, the Maya threw statues, pottery, incense, textiles, jade, gold and human sacrifices into the water as offerings to the gods of the underworld. The few human sacrifices who survived the ordeal, incidentally, were considered to have spoken with the gods, and have developed prophetic powers.
Today the region’s cenotes – some of them have been turned into theme parks, others remain blissfully undeveloped – are perhaps the most memorable places for a swim, snorkel or dive in the Yucatán. Two of the most spectacular are Cenote X’Keken and Cenote Samula, just outside the city of Valladolid.