The Calcehtok caves are said to comprise the longest dry-cave system on the Yucatán Peninsula. More than 4km have been explored so far, and two of the caves’ 25 vaults exceed 100m in diameter (one has a 30m-high ‘cupola’). The caves hold abundant and impressive natural formations; however, if you're claustrophobic, have a fear of dark spaces or don't like getting dirty, this definitely isn't for you.
Archaeologists have found and removed ceramic arrowheads, quartz hammers and other tools, and you can still see low fortifications built by the Maya who sheltered here during the Caste War.
All tours are guided and flashlights are provided. The opening of the main entrance is an impressive 30m in diameter and 40m deep, ringed by vegetation often buzzing with bees. It’s about 1m deep in bat guano at the bottom. You can opt for a basic, intermediate or adventure tour – the latter involves belly-crawling, rope descents and possibly the 7m long by 20cm wide ‘Pass of Death,’ or ‘El Parto’ (the Birth: you figure it out). Tours last one to four hours.
Note that a 'competing' entry is (logically) also named Grutas de Calcehtok and lies on the access to to Oxkintok ruin. To get to the original entrance continue straight rather than turning right toward the ruin. Both have identical signs.
The caves are 75km southwest of Mérida off Hwy 184, a few kilometers south of the town of Calcehtok. They are best reached by car.