The jungles of El Petén were once the heartland of the Mayan civilization. The sprawling empire—including parts of present-day Mexico, Belize, Honduras, and El Salvador—was once made up of a network of cities that held hundreds of thousands of people, but a millennium ago this fascinating civilization went into a mysterious decline and soon virtually disappeared. The temples that dominated the horizon were swallowed up by the jungle.

Today ancient ruins seem to emerge as if nourished by El Petén's soil. In comparison with the rest of Guatemala, which has 15 million people in an area the size of Tennessee, El Petén is relatively sparsely populated, although this is changing. Fifty years ago El Petén had fewer than 20,000 residents. Due to massive immigration from other areas of Guatemala, El Petén now has more than half a million people (almost twice the population of the entire country of Belize). Still, nature reigns supreme, with vines and other plants reclaiming everything that stands still a little too long. Whatever your primary interest—archaeology, history, birding, biking—you'll find plenty to do and see in this remote region.

Four-wheel-drive vehicles are required to get to many of the archaeological sites (but not to Tikal), while others, such as those in the Mirador Basin, are reachable only by boat or on foot. The difficulty doesn't just enhance the adventure, it gives you time to take in the exotic scenery and rare tropical flora and fauna that are with you all the way. Most major roads in the Petén are now beautifully paved, and the towns of Flores and Santa Elena bustle with activity.

The Petén may be vast and remote, but the traveler's focus takes in a far more limited area. Ruins dot the entire region, but excavation has begun on only a few of them. In the center of the region on Lago Petén Itzá sits Flores, its administrative center, and its twin town of Santa Elena, the site of the regional airport. Northeast lie the famed ruins of Tikal.