William Morales' dog was busy chasing down a gibnut (small, brown-spotted rodent) on his lush property one day in 1989, when the dog seemingly disappeared into a rock wall. Morales pressed into the 'wall' and found it was a cave mouth; inside he came upon probably the largest collection of Maya pottery ever discovered. This was Che Chem Ha (Cave of Poisonwood Water). Morales' family has been farming this land since the 1940s, and today they also conduct tours through the cave.
The cave, about 800ft long, was used by the Maya for many centuries for food storage and rituals. Narrow passages wind past ceremonial pots, many of them intact, to a stela at the end of the tunnel. Short ladders enable you to climb up rock ledges. Bring strong shoes, water and a flashlight. There are usually two daily tours lasting about 90 minutes, following an uphill jungle walk of about 30 minutes to the cave mouth.
For cave tours, contact the Morales family directly. If you don't have your own transport, a number of tour operators and lodge-based guides offer this trip, including River Rat Expeditions and Jungle Splash Tours.