Federal Bureau of Investigation

Washington, DC

DC's concrete, brutalist FBI headquarters should be seen, if only to say you have laid eyes on the single ugliest building in the entire District. When it was completed in 1975, architecture critics said it was Orwellian and resembled a dreary factory.

The building is not open to the public, except via a free tour arranged by your Congressional representative one to five months in advance, if you are a US citizen.