Yep, the X is Southeast of the Great Pyramid. Since there are many pyramids in Egypt, there's only one that's very well known. The city name rhymes with pizza.
I could be wrong but I was watch a program on Discovery Channel, and I think once or twice they actually did, attach to it. Thats why it was deemed unsafe because of the updraft.
i got my info from wikipedia, so i dunno. anyways the video led me to look in the right city, just not sure what i was looking for. airships was a big clue though, it was just logic after that