Washington D.C. (the District of Columbia) is the capital of the U.S. and the seat of its national government. Prior to its establishment in 1791, there was considerable debate among the states as to which city should serve as the nation's capital. To put an end to the dissension, the U.S. Congress (still in the stages of infancy) appropriated land from Virginia and Maryland and created a federal district that was outside of any existing state. The capital city within the district was named "Washington," in honor of George Washington. (A modest man, Washington often referred to the capital as "the Federal City," rather than by name.)
The city was originally laid out by Pierre Charles L'Enfant, who envisioned a unified design of streets and parks centered around the city's various landmarks, monuments, and important buildings. Unfortunately, L'Enfant found himself at odds with the people chosen to oversee the project, including Thomas Jefferson. L'Enfant refused to compromise his vision and, in the end, was fired from the project. Jefferson then turned to Andrew Ellicott and Benjamin Banneker, who prepared a plan based very closely on L'Enfant's original.
While L'Enfant's vision was never fully realized, his ideas are still very much evident in Washington's natural beauty. The Potomac and Anacostia Rivers were actually incorporated into the city's design, as were a number of lush, green parks. The National Mall, originally conceived by L'Enfant, was not actually implemented until the beginning of the 20th century as a part of the City Beautiful Movement. This open-area national park stretches from the Lincoln Memorial to the U.S. Capitol, with the Washington Monument standing proudly at its center, and boasts a number of gardens, reflecting pools, national monuments, and memorials. The Smithsonian Institution is headquartered in the National Mall, and many of its museums and galleries can be found there as well. The White House is open for ticketed tours, which are conducted by secret service agents. Other places of note in D.C. are Ford's Theatre (where Lincoln was assassinated), the Library of Congress, and the National Archives, where the Declaration of Independence, Constitution, and Bill of Rights can be viewed.