Ask Slashdot: Science Sights to See?

steevven1 writes: "My girlfriend and I are planning a long trip across the United States for this summer, and we'd like to see the usual sights, but we both have a bit of a geeky side, and we were trying to think of science-related marvels to see along the way. So far, we have thought of places like the Very Large Array in New Mexico and Fermilab in Illinois. Any suggestions?"