The National Zoological Park was planned by F.L. Olmstead & Co., one of the most influential and prolific American landscape architectural firms in history, and its location in the spacious and picturesque Rock Creek Valley marked an important departure from the 19th-century practice of confining zoological collections to limited areas. In addition to its important place in the history of landscape design, major scientific investigations, such as S.P. Langley's experiments in aerodynamics, are also a significant part of the Zoo's history. The National Zoo preceded the founding of the New York Zoological Park and Munich's Hellabrun Zoo, and thus may have been the first major zoo to be located in a spacious, landscaped setting. The Zoological Park's primary aim was not for the entertainment of people, but for the preservation of endangered animals indigenous to the United States. The Zoo was created at a time when American's were concerned about "the closing of the frontier" and the dominance of a new, urban, industrialized society, and the Zoo's animals were reminders to visitors of the disappearing American Wilderness. In addition to conventional animal houses, extensive pastures for grazing were planned along with natural rock quarries to contain bears, a scheme that was unsuccessful. Only two of the original buildings exist today, the Principal Animal House, now the lion house, and the New Mammal House, the present monkey house.

http://nationalzoo.si.edu/
Ring-tailed Lemur, Smithsonian National Zoological ParkRing-tailed Lemur, Smithsonian National Zoological ParkRing-tailed Lemur, Smithsonian National Zoological ParkOrangutan, Smithsonian National Zoological ParkOrangutan, Smithsonian National Zoological ParkOrangutan, Smithsonian National Zoological ParkChinese Alligator, Smithsonian National Zoological ParkChinese Alligator, Smithsonian National Zoological ParkKomodo Dragon, Smithsonian National Zoological ParkGorilla western lowland, Smithsonian National Zoological ParkGorilla western lowland, Smithsonian National Zoological ParkGorilla western lowland, Smithsonian National Zoological ParkAsian Elephant, Smithsonian National Zoological ParkAsian Elephant, Smithsonian National Zoological ParkSmithsonian National Zoo BuildingSmithsonian National Zoo - American AlligatorSmithsonian National Zoo - American AlligatorSmithsonian National Zoo - American AlligatorSmithsonian National Zoo BuildingSmithsonian National Zoo Building