After gaining traction in the years following the Civil War, organized horse racing was threatened by the strong anti-gambling sentiment popular at the beginning of the 20th century. The sport was saved by the institution of parimutuel betting and the rise of grand racetracks around the country, both of which helped to legitimize its presence. On Long Island, Belmont Park opened in 1905 with a first day attendance of more than 40,000 spectators.
