United States Capitol
The United States Capitol is home to the U.S. House of Representatives (house.gov) and U.S. Senate (senate.gov).
If you have enough time before your trip, contact your local Congressman and request a tour!
I haven't gotten a chance to take the tour of the US Capitol building but I've been told by everyone who has gone on it that it is awesome and better than the short one you get if you are able to get a tour of the Executive Mansion (The White House). The outside grounds are pretty.
Visitors to Washington DC can see the building which houses the activities of the United States Congress. The Capitol Building offers free tours and special exhibits throughout the year.
“You can tour the White House, the iconic home of America’s president, by scheduling a visit in advance. Even if you are unable to schedule a visit, walk around to the back to get a closer view of the building.”
“Take a self-guided tour of the Supreme Court, or maybe even hear an argument (when court is in session)”
“Of course the entire Smithsonian Institution is a cultural landmark; but the Air Space Museum in particular is one of our favorites.”
“Such a GORGEOUS building... it's worth a visit inside (when you're making the inevitable trek to the US Capitol).”