Picture a walk in the forest where you stumble upon a big hole in the ground. This hole opens up to a large underground cave filled with ground water and catfish. The water is 18 degrees Celsius and you see stalactites hanging above your head and stalagmites protruding below your feet.
This is where we went swimming. The cool water was a welcomed after a day of walking in the heat, and no one lost any limbs to the catfish.
National Geographic tells me that the Mayans used these cenotes to determine the right time of year to undertake their harvests. When the sunrays would shine down in the pool of water and be reflected straight up and not onto the inner walls, the Mayans new the sun was a its zenith and that it was time to harvest. This happened twice a year.