Washington, D.C. (pronounced /ˈwɒʃɪŋtən ˌdiːˈsiː/; formally, the District of Columbia and commonly referred to as Washington, the District, or simply D.C.) is the capital of the United States, founded on July 16, 1790. The City of Washington used to be a separate municipality within the District of Columbia until an Act of Congress in 1871 effectively merged the City and the District into a single entity. It is for this reason that the city, while legally named the District of Columbia, is known as Washington, D.C. The city is located on the north bank of the Potomac River and is bordered by the states of Virginia to the southwest and Maryland to the other sides. The District has a resident population of 588,292; however, due to commuters from the surrounding suburbs, its population rises to over one million during the workweek. The Washington Metropolitan Area, of which the District is a part, has a population of 5.3 million, the eighth-largest metropolitan area in the country.
The National Mall is a large, open park area in the center of the city. Located in the center of the Mall is the Washington Monument. Also located on the mall are the Lincoln Memorial, the National World War II Memorial at the east end of the reflecting pool, the Korean War Veterans Memorial, the Vietnam Veterans Memorial, and the Albert Einstein Memorial.[98] The National Archives houses thousands of documents important to American history including the Declaration of Independence, the United States Constitution, and the Bill of Rights.
Located directly south of the mall, the Tidal Basin features rows of Japanese cherry blossom trees that were presented as gifts from the nation of Japan. The Franklin Delano Roosevelt Memorial, Jefferson Memorial, and the District of Columbia War Memorial are located around the Tidal Basin.
The Smithsonian Institution is an educational foundation chartered by Congress in 1846 that maintains most of the nation's official museums and galleries in Washington, D.C. The U.S. government partially funds the Smithsonian, thus making its collections open to the public free of charge. The most visited of the Smithsonian museums in 2007 was the National Museum of Natural History located on the National Mall. Other Smithsonian Institution museums and galleries located on the mall are: the National Air and Space Museum; the National Museum of African Art; the National Museum of American History; the National Museum of the American Indian; the Sackler and Freer galleries, which both focus on Asian art and culture; the Hirshhorn Museum and Sculpture Garden; the Arts and Industries Building; the S. Dillon Ripley Center; and the Smithsonian Institution Building (also known as "The Castle"), which serves as the institution's headquarters.