Along with the increasingly growing popularity, a large number of people started to realize the potential for financial gain. Landowners were regularly maintaining baseball parks to rent to baseball clubs by the 1850. Baseball teams customarily collected donations from fans to cover the costs. The Union Grounds in Brooklyn, the first fully enclosed baseball park, was finished in 1862. this style of park soon gained a big popularity for owners were able to sell food and drink to spectators without competition from street vendors. The National Association of Base Ball Players, an organization formed in 1858, stopped members from taking payment for playing baseball. During the early 1860s ballpark owners gained large profits, however, at the same time the amateur ball players offered free entertainment. Pressure from players finally forced the NABBP to change its policy in 1868 and allow players to accept money, which marked the birth of professional baseball. The first professional baseball team, the Cincinnati Red Stockings, began playing in 1869. They traveled the country that year, playing in front of numerous fans and got 60 games winning with no one loss. Soon baseball’s promoters start forming professional baseball clubs in cities across the Northeastern and Midwestern United States. By 1870 professional players outnumbered amateurs in the NABBP and the remaining amateurs withdrew.