The National Zoo was created by an Act of Congress in 1889 for “the advancement of science and the instruction and recreation of the people.” In 1890 it became a part of the Smithsonian Institution. Three well-known people planned the Zoo: Samuel Langley, third Secretary of the Smithsonian; William T. Hornaday, a conservationist and head of the Smithsonian's vertebrate division; and Frederick Law Olmsted, a landscape architect. They designed a new zoo to show animals for the public and to serve as a refuge for wildlife, such as bison and beaver, which were rapidly vanishing from North America.