Tucson's 20th-century growth occurred after World War I, when veterans with damaged lungs sought the dry air and healing power of the sun, and again during World War II with the opening of Davis-Monthan Air Force Base and the rise of local aeronautical industries. It was also around this time that air-conditioning made the desert climate hospitable year-round.

Today, many transplants come from the Midwest and nearby California because of the lower housing costs, cleaner environment, and spectacular scenery. And despite the ubiquitous strip malls and tract-home developments, this college town has Mexican and Native American-cultural influences, a striking landscape, and all the amenities of a resort town. High-tech industries have moved into the area, but the economy still relies heavily on tourism and the university, although, come summer, you'd never guess. When the snowbirds and students depart, Tucson can be a sleepy place.