Maya palace suddenly expands.

Last year, an archaeological team led by Arthur Demarest of Vanderbilt University in Nashville explored Cancuen, an ancient Maya city that investigators have long characterized as physically small and unimportant in Maya history. As Demarest walked atop a jungle-covered hill holding the remains of Cancuen's presumably modest palace, he suddenly plunged into a thicket of vegetation up to his armpits. He had stumbled into a palace courtyard long obscured by dense foliage.

"That's when I realized that the entire hill was a three-story building, and we were walking on top of the roof," he says.

Demarest and his coworkers announced last week that the Cancuen palace represents one of the largest, most elaborate, and best preserved residences of ancient Maya kings. The 1,300-year-old structure features more than 170 rooms and 11 courtyards.

Cancuen, which means place of serpents, lies in a remote, forested region of Guatemala. Its largely camouflaged palace covers about 270,000 square feet, Demarest says. A preliminary survey of the structure uncovered a maze of hundreds of rooms with 20-foot-high, arched ceilings.

The researchers have also explored homes and workshops of affluent artists and craftsmen who lived near the palace.

Demarest suspects that the palace housed representatives of the many allies of Cancuen's rulers, who belonged to a dynasty that had assumed power by A.D. 300. Evidence at the site suggests that it prospered for centuries as a hub of commerce and avoided wars with its neighbors. The kingdom focused on controlling the region's trade in precious items, such as jade jewelry, pyrite for making mirrors, and obsidian for knife blades.

By emphasizing trade, Cancuen's rulers stand in contrast with most Maya kings, who waged constant war with rival city-states, encouraging the collapse of the region's major population centers around A.D. 900.