I’ll see you one Flughafen and raise you one New York City (circa 1992, originally built for the New York World’s Fair 1964-65 where I saw it, lo, those many years ago.) As originally shown, there were aircraft flying in and out of the airports and the article says there are 895,000 individual buildings. As I recall, one saw it by standing on a moving sidewalk, but I may be mistaken about that last detail.