Dan Flores

Then at solstices and other special times of year, it hosted grand ceremonies to which the outlying residents made holy pilgrimages. At those times, Chaco gathered a population of some 40,000. Looking down now on its buildings and avenues, one suspects both the ceremonies and the nightlife must have been epic.

Chaco America almost seems foreign in the modern United States, as if lifted from the Middle East. The agricultural revolution arrived in this region 1,300 years before the city existed, and pollen studies indicate this development produced two immediate environmental effects.

Chaco America almost seems foreign in the modern United States, as if lifted from the Middle East. The agricultural revolution arrived in this region 1,300 years before the city existed, and pollen studies indicate this development produced two immediate environmental effects.

Chaco America almost seems foreign in the modern United States, as if lifted from the Middle East. The agricultural revolution arrived in this region 1,300 years before the city existed, and pollen studies indicate this development produced two immediate environmental effects.

Human populations skyrocketed, and crops that needed to be boiled before you could eat them meant that daily cooking fires soon reduced a robust pinyon-juniper woodland to desert. This became a world in need of priests who could intervene with the gods.

Human populations skyrocketed, and crops that needed to be boiled before you could eat them meant that daily cooking fires soon reduced a robust pinyon-juniper woodland to desert. This became a world in need of priests who could intervene with the gods.

Human populations skyrocketed, and crops that needed to be boiled before you could eat them meant that daily cooking fires soon reduced a robust pinyon-juniper woodland to desert. This became a world in need of priests who could intervene with the gods.

Sitting and admiring the sprawling hemispheric architecture of Chaco's largest structure, Pueblo Benito, as its lines and shadows shimmer in the afternoon sun, I know this is a place that reveals much about humanity. Sarah passes the water bottle over to me and reading my mind sums it up.

Sitting and admiring the sprawling hemispheric architecture of Chaco's largest structure, Pueblo Benito, as its lines and shadows shimmer in the afternoon sun, I know this is a place that reveals much about humanity. Sarah passes the water bottle over to me and reading my mind sums it up.

Sitting and admiring the sprawling hemispheric architecture of Chaco's largest structure, Pueblo Benito, as its lines and shadows shimmer in the afternoon sun, I know this is a place that reveals much about humanity. Sarah passes the water bottle over to me and reading my mind sums it up.

It wasn't until the 1880s that anyone built a larger building than that in America. In its time, this city lasted longer than Washington, D.C. has so far.

It wasn't until the 1880s that anyone built a larger building than that in America. In its time, this city lasted longer than Washington, D.C. has so far.

It wasn't until the 1880s that anyone built a larger building than that in America. In its time, this city lasted longer than Washington, D.C. has so far.

Chaco and its satellite hamlets survived, in fact, for 340 years. The shorthand version of its collapse is that it all ended with a series of droughts across the Southwest, and that's true. But the many archaeologists who have interpreted Chaco know that much more happened here.

Chaco and its satellite hamlets survived, in fact, for 340 years. The shorthand version of its collapse is that it all ended with a series of droughts across the Southwest, and that's true. But the many archaeologists who have interpreted Chaco know that much more happened here.

Chaco and its satellite hamlets survived, in fact, for 340 years. The shorthand version of its collapse is that it all ended with a series of droughts across the Southwest, and that's true. But the many archaeologists who have interpreted Chaco know that much more happened here.

When the rain stopped coming, the farmers seemed to act abruptly, dropping their digging sticks in the fields, turning their backs on the grand religious gatherings at Chaco, and relocating across the southwest. Some went north to what we now call Mesa Verde's Cliff Palace in present Colorado.

When the rain stopped coming, the farmers seemed to act abruptly, dropping their digging sticks in the fields, turning their backs on the grand religious gatherings at Chaco, and relocating across the southwest. Some went north to what we now call Mesa Verde's Cliff Palace in present Colorado.

When the rain stopped coming, the farmers seemed to act abruptly, dropping their digging sticks in the fields, turning their backs on the grand religious gatherings at Chaco, and relocating across the southwest. Some went north to what we now call Mesa Verde's Cliff Palace in present Colorado.

Most of the people who abandoned the Chacoan world congregated along the upper Rio Grande, eventually founding towns still home to their descendants, the Pueblo peoples famous for their apartment-like villages, geometrically painted pottery, and turquoise jewelry. Why did Chaco collapse in what sounds like a fit of pique?