If you’ve ever ventured inland on Yucatan Peninsula, you may have noticed a distinct lack of major rivers in the area. This is because the prevailing rock type is porous limestone and the water makes its way into a network of underground channels and caverns. There are in fact thousands of freshwater sinkholes in the area – known as dzonots by the Maya or cenotes by the Spanish – which no doubt would have been critical in supporting the large Mayan cities that once existed.
Close to the colonial town of Valladolid is Cenote X’kekén (also known as Cenote Dzitnup) which is open today for visitors to swim in. There’s even been two ropes installed to aid less confident swimmers.