Smithsonian National Zoological Park
Overview
The Smithsonian National Zoological Park, commonly known as the National Zoo, is one of the oldest zoos in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and as part of the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

, 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 acres (66 ha) urban park located in northwest Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

 that is 20 minutes from the National Mall by Metro to the Woodley Park station.
 
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