Arcadia is an affluent suburban city of more than 50,000 residents at the base of the San Gabriel Mountains.  Home to the Santa Anita Park racetrack and the Los Angeles County Arboretum and Botanical Garden, Arcadia grew in the post-World War II era as developments of tract homes took the place of ranches and farms.  Today, Arcadia ranks as one of the most expensive housing markets in the United States.