Denver was barely 10 years old in 1868 when visionary pioneers such as Alfred B. Case and Jacob W. Downing began amassing real estate holdings far from downtown, speculation that paid off when the newly arrived railroad led to a population explosion. With the opening of the Whittier School in 1883—the largest elementary school in the city—a domain for prairie dogs evolved into a middle-class haven of fine Victorian homes. Buffalo Bill Cody's sister even called the Whittier neighborhood home. The convenience and reliability of an expanding streetcar system brought the lifeblood of the city into the neighborhood. Whittier and its residents were also blessed with the establishment of a large, 320-acre park just to the east. This park, transformed from native prairie to irrigated forest, became one of the biggest attractions in Denver—City Park.