Washington 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. An Act of Congress in 1871 created a single government for the entire federal territory, effectively merging 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, its population rises to over one million people during the workweek, due to commuters from the surrounding suburbs. Washington, D.C. has a growing, diversified economy with an increasing percentage of professional and business service jobs. 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. 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.