In Arizona: A City Has to Be Built

When seen from the exit leading off Interstate 17, 73 miles north of Phoenix, it shimmers in the summer heat, a mirage-like vision that somewhat resembles parts of battlestar Galactica crash-landed in the desert. Arcosanti. The name alone suggests hallucination. It is derived from arcology (architecture concerned with ecology) and cosanti (Italian for "thing before"). An engineer showing off the unfinished structure's apses and arches proudly describes it as "the city of the future taking shape in the state of the past."

The idea behind Arcosanti is beguilingly simple: since cities shape society,...