Travelers in the mood for rainforests and ruins tend to take aim at Belize and Costa Rica, never considering southern Mexico. The result: Chiapas, though home to spectacular jungled Maya outposts, sees relatively few visitors, most of them of the Aussie-backpacker variety. Which is fine. Take a private five-day tour with the archaeologist guides at New Mexico–based MayaSites (from $700; mayasites.com). The trip starts in Palenque, the pyramid-punctuated Maya city. Later, guests take a canoe ride down the Usumacinta River—Crocs! Toucans!—to the mossy temples at Yaxchilán. Opt to sleep at the Escudo Jaguar Ecotourist center, an hour upriver from Yaxchilán. From there, Agua Clara—a series of waterfalls feeding half a dozen travertine swimming holes—is an easy day trip.