As America's 76 million baby boomers reach retirement age, what they need—and want—in their living arrangements will change dramatically. Some boomers will seek out suburban gated communities such as Leisure World in Seal Beach, Calif., which explicity excludes primary residents under the age of 55. Architect Matthias Hollwich is banking on a different trend—the desire of older Americans to live in diverse, higher-density communities, with a host of services and activities. And no matter where the baby boomers choose to retire, Michael Graves wants their surroundings to be perfectly, universally accessible. Read on to learn more.