Islamic terrorists have pretty much given up on industrial and military targets, and shifted most of their efforts to hotels and shopping malls. The main reason is security, and traffic. Military and industrial facilities have a lot less traffic, and that traffic can more easily be controlled (troops and employees are more disciplined). But hotels and malls encourage traffic, the more the better. Since most of that traffic are customers, you can't impose a lot of discipline. Hassle the customers too much, they go elsewhere, and the hotel or mall goes out of business. This security at these "soft" targets is much more difficult, and much easier to penetrate. Thus the increasing number of successful terror attacks on hotels and malls.