Sun City, the other great model, is a town of 46, 000 people built by Del Webb on the other side of Phoenix from Anthem.

ECONOMIST: The growth of private communities

Pulte's Del Webb unit, for example, has built 41 of these boomer complexes--in the suburbs of Boston, New York and Chicago, among other places--and now plans to invade metro Atlanta and Minneapolis.

FORBES: Magazine Article

Del Webb houses are for active, 55-plus adults.

FORBES: PulteGroup CMO Fine Tunes Marketing, Research