For a playful dose of architectural genius, visit Gaudí's colorful Parc Güell. Gaudí intended this 30-acre garden to be a 60-residence housing project — a kind of gated community. As a high-end housing development, the project flopped. But a century later, as a park, it's a huge success. For more information on the Rick Steves' Europe TV series — including episode descriptions, scripts, participating stations, travel information on destinations and more — visit www.ricksteves.com.