Washington D.C. is the capital of the United States. It is home to the entire federal government, including the Congress, the Supreme Court and the President. There are numerous museums and national monuments scattered along the city that highlight the history and important people that helped shape this country into what we see today. Many of these museums and monuments are clustered in an area known as the National Mall - a 2 mile strip that extends from the State Capital building to the Lincoln Memorial. And it's all free.