The National Zoological Park, commonly known as the National Zoo, is one of the oldest zoos in the United States, and as part of the Smithsonian Institution, does not charge admission. Founded in 1889, its mission is to provide leadership in animal care, science, education, sustainability, and visitor experience. The National Zoo has two campuses. The first is a 163-acre (66 ha) urban park located in northwest Washington, D.C. that is 20 minutes from the National Mall by Metro to the Woodley Park station, or downhill walk from the Cleveland Park station. The other campus is the 3,200-acre (1,300 ha) Smithsonian Conservation Biology Institute (SCBI; formerly known as the Conservation and Research Center) in Front Royal, Virginia. On this land there are 180 species of trees, 850 species of woody shrubs and herbaceous plants, and 40 species of grasses. There are also 36 different species of bamboo. The SCBI is a non-public facility devoted to training wildlife professionals in conservation biology and to propagating rare species through natural means and assisted reproduction.