Steve F. Udvar-Hazy center (Smithsonian museum)

Exterior of the museum
Exhibition map
Airplanes and spacecrafts hung in the air and layes on the ground
Lockheed SR-71A Blackbird – much bigger than you think
Seeing the actual Concord was quite interesting. Only knew it by word from playing monopoly games until then.
Space shuttle discovery
Spacecrafts and devices
Jet flights
Manufacture hangar area

The most impressive flight among many airplanes here was Concord for me. Of course, first time ever to see an actual space shuttle was very interesting, too.