Forest Park is the largest wilderness park within city limits in the United States, covering more than . Portland is also home to Mill Ends Park, the world's smallest park (a two-foot-diameter circle, the park's area is only about 0.3 m2). Washington Park is just west of downtown and is home to the Oregon Zoo, Hoyt Arboretum, the Portland Japanese Garden, and the International Rose Test Garden. Portland is also home to Lan Su Chinese Garden (formerly the Portland Classical Chinese Garden), an authentic representation of a Suzhou-style walled garden. Portland's east side has several formal public gardens: the historic Peninsula Park Rose Garden, the rose gardens of Ladd's Addition, the Crystal Springs Rhododendron Garden, the Leach Botanical Garden, and The Grotto.