While in DC - given that it's summer and HOT there (lived there for a couple of years) - recommend the hop/on hop/off shuttle to get you between places. Saves wear and tear. The most amazing (and least discussed) memorial is the Korean War Memorial. As you face the Lincoln it is on your left. It looks like the soldiers are walking through rice paddys. Gives you chills - ESPICALLY at night. Make sure you take a night tour also - AMAZING. Arlington Cemetary is a must. The NEWSeum on Penn Avenue is brand new - has a section of the Berlin Wall and tells the history of news reporting of world events.