Prospect Park Alliance. We take care of Brooklyn’s Backyard. Official page of Prospect Park and the Prospect Park Alliance. Prospect Park Alliance is the non-profit organization that sustains "Brooklyn's Backyard," working in partnership with the City of New York. The Alliance was founded in 1987 to help restore the Park after a long period of deterioration and decline. Today, the Alliance provides critical staff and resources that keep the Park green and vibrant for the diverse communities that call Brooklyn home. The Alliance cares for the woodlands and natural areas, restores the Park's buildings and landscapes, creates innovative Park destinations, and provides free or low-cost volunteer, education and recreation programs.