Capitol Building
is really United States Capitol, Washington, DC
Real place, still recognisable
Real-world photo: Wikimedia Commons
In the game
A ruined battleground where super mutants and Talon Company mercenaries fight room by room.
The real place
Seat of the US Congress since 1800, crowned by its cast-iron dome.
Visiting
Free guided tours start at the Capitol Visitor Center; booking ahead is a good idea.