Washington D.C. is the capital of the United States located on the Potomac River. It was founded in 1791 and named after George Washington, the first U.S. president. The city has a unique design and was purpose-built as the nation's capital based on a plan by Pierre L'Enfant. Major landmarks include the White House, U.S. Capitol, Washington Monument, Lincoln Memorial, and numerous museums and memorials honoring important figures in American history.