The first day out of Mérida, heading south towards the Puuc Route, we stopped at Oxkintok and the Calcehtok Caves.
The ruins at Oxkintok were a surprise. They hardly feature in some guidebooks, and we were expecting something small and hardly excavated. Instead, after driving through kilometer after kilometer of bare countryside, at last we came to the usual impeccable entryway, with its nominal entry fee to the site's manicured lawns, carefully reconstructed buildings, and a slew of gardeners, two of whom tried to be helpful-for-hire until we politely avoided them. The ruins were a huge array of buildings in various states of repair, from perfectly reappointed to still a giant green bulge in the ground. The best of the lot by far was the Labyrinth, a medium-sized pyramid containing three levels of interconnected tunnels, two exits, and a balcony, all barely lit by clever light shafts which shot squarely though the walls for perfect beams of sunlight to come in. You could tell how many levels deep you were in the pyramid by the strength of the light. It should have been creepy (there were bats), but it was beautiful, lit brown-gold by the light shafts. Plus, of course, it's fun to explore, with some small holes to squeeze through for drama but no actual difficulty. (It helps that we go everywhere with flashlights.)
Then on to the caves. These were surprisingly close to the ruins, as though the Maya built them with tourists in mind; present-day tourist facilities ignore them, however, which means that there is no entry fee, and the site is a bit eerie. The caves start with an enormous hole in the ground, full of tall trees reaching towards the sky past the roots of the other trees at ground level a hundred feet above them. We climbed down a rickety green ladder into the only real jungle we saw in the Yucatan -- palms and banana trees and a watching mot-mot. To get deeper into the caves, we had to scramble a bit down the slope and get out the flashlights.
The caves supposedly go for two kilometers. We didn't go that far, but we went a long way -- long enough that I got scared, and even my cave-loving partner eventually decided that further progress wouldn't be totally safe. There were some beautiful formations -- a lacy white stalagmite which had tiny indentations, or furrows, full of water which looked like rice paddies, a good four lovely feet tall; another white wedding cake-like one; a flat spot covered with tiny winding pathways like worm-eaten wood; and huge sparkly things like sequined beach balls. Just spectacular. But muddy. The deepest rooms were strangely steamy--very warm and wet and full of mosquitoes.
Both sites are very much worth visiting -- Oxkintok for its unusual buildings and low crowding, Calcehtok for its lovely formations. Neither, though, is for the claustrophobic, and I wouldn't want to visit the caves (which are totally without facilities, trails, or safety materials of any kind) without flashlights -- or with children who didn't know when to do what they were told.