Chaco, New Mexico
Credit: David Hiser / Getty Images

When one thinks of the best places for touring ancient dwellings, Greece, Egypt, and Italy quickly spring to mind. But smack dab in the American Southwest is the area's densest collection of pueblos, dating back to the year 850 A.D., which showcase the impressively ahead-of-their-time organizational, engineering, and masonry skills of the pioneering Pueblo population with 15 major complexes. Located within Chaco Culture National Historical Park, Chaco was a major cultural center between 900 and 1150 A.D. but became an early victim of climate change; residents began migrating out of the canyon shortly after the arrival of a 50-year drought in 1130 AD.

Wade Davis and Robert F. Kennedy Jr. visited Chaco Canyon during the making of Greg MacGillivray's IMAX documentary, Grand Canyon Adventure: River at Risk"It's just a very humbling thing to see the scale of places like Chaco Canyon or Mesa Verde and realize that [we] had these sort of networks of roads and a pretty high level of civilization complexity that were clearly wiped out, if you will, by climactic change."

Getting there: As part of the U.S. National Park Service, visiting Chaco is a simple – and multi-optioned – affair. Enter at the Visitor Center, which features an information desk, museum, theater, bookstore, and gift shop. A paved road offers self-guided trails to five major Chacoan sites, each of which takes an hour or less to visit. There are separate trails for biking and hiking and from April through October, there are a number of specialized hikes and programs, including astronomy events courtesy of the Chaco Night Sky Program.