Interesting. I knew about Falls Church, but I used to live in a part of Alexandria that's in Fairfax County and never realized another part was separate. I just looked at a map, and that's a really weird boundary. I guess it makes sense to somebody.
I didn't know that either. I have a relative who bought a house in the part that's in Fairfax County back in the 1950s, and his mailing address has always been "Alexandria, VA." I had no idea it wasn't part of the "real" Alexandria. Still, he's inside the Beltway so that means something.