Balboa Park is a 1,200 acre (4.9 km²) urban cultural park in San Diego, California, United States named after the Spanish explorer Vasco Núñez de Balboa. Many of the trees here were planted by the famous American gardener Kate Sessions. Placed in reserve in 1835, it is one of the oldest sites in the United States dedicated to public recreational usage. Besides open areas and natural vegetation, it contains a variety of cultural attractions including museums, theaters, gardens, shops and restaurants as well as the San Diego Zoo. Balboa Park was declared a National Historic Landmark in 1977. The park is managed and maintained by the City of San Diego Parks and Recreation Department.