The O'odham Indians use the word 'Hohokam' ('all used up') for the ancestors who mysteriously abandoned this adobe city and the intricate irrigation system that sustained it. Despite the proximity of busy highways, it remains impressive, with a central platform, dwellings, ceremonial ball court and hints of a surrounding 1000-mile canal network that was one of precontact America's greatest engineering feats. An interpretive trail and small museum take you deeper inside a culture that flourished here until the 15th century.