PAGOSA SPRINGS - Chimney Rock Archaeological Area offers a vivid example of the value of preserving archaeological sites intact. As virtual time capsules, cultural sites can serve as laboratories for studying the lessons that ancient civilizations may have to offer modern mankind.

A film crew from National Geographic was in Southwest Colorado last week to document the ongoing research at Chimney Rock for an upcoming documentary on Collapse: How Societies Choose to Fail or Succeed, a book by Pulitzer Prize-winning author Jared Diamond. Collapse includes case studies on several failed ancient civilizations, including the Chacoan people of the Four Corners.

Chacoan scholar Steven Lekson of the University of Colorado, who was interviewed for the documentary, is supervising excavations this summer of the Chimney Rock Great House Pueblo.

Lekson, author of The Chaco Meridian, Centers of Political Power, believes Chimney Rock was part of a Chacoan Empire that stretched south into Mexico.

Lekson speculates that the Chacoans may have interacted with the Aztec and Toltec civilizations and strived to emulate them. As evidence, he cites design similarities in the architecture at New Mexico's Chaco Culture National Historical Park and the great Meso American cultural sites in Central America.

"At Chaco Canyon, we've found cacao, copper, macaw feathers and turquoise, and deer and elk bones," Lekson said. "All of that came from far away."

Both Diamond and Lekson hypothesize in their books that the Chacoan culture, which existed from about 650 AD to almost 1200, may have crumbled as the result of environmental pressures, such as extended drought, combined with social inequality.

"This is why archaeology might matter," Lekson said. "Maybe some high-level lawmaker in D.C. will use these lessons of history in an intellectual context as policies are made. Chimney Rock is a superb place to tell this story, and it will be told a little differently after this work is done."

Imitations of the Great Houses of Chaco Canyon have been found in Utah, Arizona, elsewhere in New Mexico and at Chimney Rock. These outliers were connected to Chaco by ancient roadbeds, which are still visible stretching across the vast desert landscapes of the Four Corners.

Lekson said the Great Houses were built on a scale that suggests they were inhabited by a form of Chacoan royalty.

"You don't build cities like this if you're eking out a living," Lekson said. "There were kings, and there were commoners."

But like other failed civilizations, the empire may not have been sustainable when environmental difficulties exacerbated underlying social tensions, according to Lekson.

"The Chacoans dissolved into warfare as the people rejected the social structure," he said.

Lekson believes there is evidence that the social upheaval was accompanied by an ancestral Puebloan Renaissance of sorts.

"There appears to have been an artistic explosion, where the conservative geometric patterns on pottery were replaced by artistic mural experimentation," he said.

As the system fell into disarray, the people fled to locations where they could build new villages in defendable sites, such as Mesa Verde and other cliff-dwelling communities, Lekson said.

"They were in the cliffs because they were scared," he said. "They were circling the wagons."

Lekson further postulated that the modern Pueblo tribes of New Mexico, who are descendants of the Chacoans, have developed into more egalitarian societies in intentional contrast to the authoritarian, and less sustainable, Chacoan system of the past.

Ann Bond is the public affairs specialist for the San Juan National Forest.