Washington DC, as many other American cities, is really famous due to the American movies. So, I suppose you watch Lincoln Memorial thanks to The Simpsons or the film Forrest Gump.
This is the capital of the United States since 16th July in 1790. Washington DC is located on the country's Pacific coast, on the north of the Potomac River and surrounded by the states of Maryland and Virginia. There are many interesting museums, interesting historical sites such as The National Mall where you could see the the Washington Monument, Lincoln Memorial, The Reflecting Pool, The National Archives (where you could see The Declaration of Independence, The United States Constitution and the Bill of Rights); besides, the Capitol and the White House.
Thus, if you watch the following videos, you can know Watshington DC better. I hope you'll like it!