 The pond, originally known as Belvedere Lake, abuts Belvedere Castle as well as the Delacorte Theater, and contains a variety of turtles and fish.The lawn is composed of of oval-shaped land, which is used not only for sports but also for concerts.The lawn and pond occupy the almost flat site of the rectangular, Lower Reservoir, which was incorporated into the Greensward Plan for Central Park, designed by Frederick Law Olmsted and Calvert Vaux.