1. As you point out, right next to Pentagon and federal government. 2. Good transportation: right on the Metro and literally across the street from National Airport. 3. If you're going to have 2 headquarters, having them be on opposite coasts makes sense. 4. And I think another one that is pretty unique to Crystal City is that Amazon and their employees definitely want to be in a downtown, urban environment. However, most of the other cities on the list were either extremely crowded downtown, available sites were actually more out in the 'burbs, or the cities were far down in what a lot of people would consider "2nd tier" (or 3rd tier) cities. Crystal City is basically an urban suburb of DC that you could easily see having a great "vibe" for an HQ2, but still has room for Amazon to build out.