Seems unlikely that advanced aliens would need to resort to military conquest when economic conquest would be cheaper and more efficient. They could probably trade some of their minor technology, like nuclear fussion, light-weight alloys, or computers on the open market here and buy anything they needed from us. Instead of having to bomb us into oblivian and then do all the work of shifting through the debry, they could sell us a small nuclear fussion plant that could power a city, recieve in exchange enough materials to make a hundred more, trade a few of those for more material, and so on. The items they give us would cost them no more than the materials they would consume conquering us (bombs, etc.), and we would deliver whatever they want from us to their door instead having to dig through a radioactive rubble.

The gold standard for the country would probably be the Smithsonian group in the National Mall. You have the National Museum of Natural History and the National Air and Space Museum. A few blocks north is the Marian Koshland Museum. There is the National Zoological Park for a nice biology lesson. An hour drive away in Chantilly, VA you have a REALLY big air and space museum that is a branch of the National Air and Space Museum, only about 4 times as big, called the National Air and Space Museum's Steven F. Udvar-Hazy Center.

I can remember as a kid playing around randomly with my chemistry set. Is this how the world ends, not with a bang nor a whimper, but with some kid saying, "Gee, I wonder what happens if I cross flesh eating bacteria with dandelion pollen"?