Something occurs to me. Have you ever wondered why the terrorist attacks never happen in Saudi Arabia, Qatar, the U.A.E and other of these oil monarchy/dictatorships which the Islamic extremists hate?
I mean Dubai is really the perfect example of this. If this world's tallest skyscraper in Dubai is not the "world's perfect terrorist target", I don't know what is.
http://creativeoverflow.net/wp-content/uploads/2014/05/burj-khalifa-1.jpg
Not only is Dubai totally "westernized", what the muslim extremists hate the most, but it's also a symbol of all the wealth being concentrated into the hands of a few, what the muslim extremists also hate.
SO, why hasn't an airliner already gone into that building?
Probably because all these places are analogous to the businesses which pay protection money to the mafia. And the mafia is analogous to the muslim terrorists.
As long as they keep paying the protection money, in the form of financing the terrorists, then their skyscrapers don't get hit with airliners. lol