Italy
Why visit a mental hospital? Because the historic grounds and buildings are beautiful (if a little run-down and creepy). On top of that, you can see some great views from here of the D.C. skyline. The hospital was founded in 1852 as the first major government-run mental institution, and at its peak
housed 7,000 patients, which at one point included both President Lincoln's and President Garfield's assassins. The hospital still operates, but on a much reduced scale. The Department of Homeland Security has plans to relocate here in 2021. Construction may have already started, as money for the purpose was requested in the 2016 Federal budget. You aren't really supposed to drive into the facility, but a little smooth talking at the gate may get an architecture buff inside.
Listen to the audio guide for St. Elizabeths Hospital Free on WIP — starts by itself when you arrive, even with the screen off