Craig Childs in the LA Times:
North Americans in the early centuries AD were gathering into population centers, dabbling in metallurgy and domesticating animals such as dogs and turkeys. Public works were going full swing. Beneath the modern city of Phoenix you will find remains of several hundred miles of mathematically engineered irrigation canals that once fed a hydraulic society on a par with early Mesopotamia.
Structures now known as “great houses” once stood in the Four Corners region — where New Mexico, Colorado, Utah and Arizona meet. They were masonry compounds rising as tall as five stories, their ground plans going on for acres, interiors honeycombed into hundreds of rooms including massive, vaulted ceremonial chambers.
Such an architectural landscape defies cliches about this continent’s history. Add into this picture trade routes extending more than 1,000 miles along which goods were being moved from Central America into what is now the United States. These goods included copper implements, live tropical birds and, now we know, chocolate.
Chocolate is the cherry on top of Southwest archaeology, and it tips the balance of perspective.