<P> The National Mall contains and borders a number of museums of the Smithsonian Institution, art galleries, cultural institutions, and various memorials, sculptures, and statues . The park receives approximately 24 million visitors each year . </P> <P> In his 1791 plan for the future city of Washington, D.C., Pierre (Peter) Charles L'Enfant envisioned a garden - lined "grand avenue" approximately 1 mile (1.6 km) in length and 400 feet (120 m) wide, in an area that would lie between the Capitol building and an equestrian statue of George Washington to be placed directly south of the White House (see L'Enfant Plan). The National Mall (proper) occupies the site of this planned "grand avenue", which was never constructed . Mathew Carey's 1802 map is reported to be the first to name the area west of the United States Capitol as the "Mall". </P> <P> The Washington City Canal, completed in 1815 in accordance with the L'Enfant Plan, travelled along the former course of Tiber Creek to the Potomac River along the present line of Constitution Avenue, NW (formerly B Street, NW) and south around the Capitol, thus defining the northern and eastern boundaries of the Mall . Being shallow and often obstructed by silt, the canal served only a limited role and became an open sewer . The portion of the canal that traveled near the Mall was covered over in 1871 for sanitary reasons . </P> <P> The Smithsonian Institution Building ("The Castle"), constructed from 1847 to 1855, is the oldest building now present on the National Mall . The Washington Monument, whose construction began in 1848, stands near the planned site of its namesake's equestrian statue . </P>

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