One of the places I enjoyed visiting the most was the Newseum, which opened 6 months ago. It's a museum that takes you through all the major world events in the past century , even before that, and how the media covered those events.
Plenty of images, tapes and invaluable collections.
Here are some photos that you may find interesting:
This is a poem hand-written by Saddam Hussein.
Remember Daniel Pearl, the American journalist who was kidnapped and beheaded in Pakistan a few years back? This is his passport and laptop.
In the first gulf war in 1991, the coalition troops struck a weapon factory in Iraq. Peter Arnett from CNN later revealed that it was actually a milk factory for children and showed this packet of milk from the factory to prove that. Self-explanatory.