What makes the Hohokam noteworthy is the development of irrigation works. The earliest... dates from some 2,000 years ago.... They built dams that redirected the flow of water into irrigation canals, some of them... extending for more than twenty-five miles.... They built flat-topped pyramids and ball courts, where they used rubber balls imported from Central America. The Hohokam may also have been the first to use the technique of etching with acid in their remarkable designs on marine shells.

Man's Rise to Civilization (1968)