Mexico has every kind of site from every era of the Maya and beyond: from grand cities to humble sacred spots; from Preclassic to Terminal Classic; from easily accessed to difficult-to-reach destinations.

All archaeological sites are managed by El Instituto Nacional de Antropología e Historia (INAH, tel. 4040-4624 and 4040-4300, www.inah.gob.mx). INAH reports that there are 29,000 registered archaeological sites in all of Mexico, of which 180 are open to the public. A good many of those are in the Maya zone.

There are increasingly more restrictions about climbing the pyramids. All are site specific and are enforced both for your safety and the park guards’ sanity. For example, at Palenque, the Temple of Inscriptions and the Temple of the Jaguar are closed to climbers, but the Cross Group and the Palace are still open. At Chichén Itzá, forget about climbing anything.

As a rule, if you see a “no climbing” sign, abide by it. If you don’t see a sign, be careful—especially in the rain and early-morning mist when the limestone gets very slick.