How did they know??

         Everyone has to come up with a plan for something no matter what it is they do. Which means that these terrorist had to be planning this attack for a long while. How did they know that our technology wouldn't detect a knife or a gun? How did they know that they could get so far with such a mischievous plan?  "... expect the response, or a reaction, from the enemy." Anyone with common sense knew that we would come back with fire. For the longest time we all inferred that something would soon enough happen. We just didn't know how soon. They're martyrs were using a religion to cover up what they wanted revenge on. Bin Laden was very clandestine about his plan, and figure out what he needed to know to deliver his revenge. Todays technology is more advance then what we had ten years ago " all of their equiptment and gates and technology will not prevent, nor harm, except by gods will." Obviously, Bin Laden knew our weak spots and took advantage of them. Because of the fact that America knew this was coming some day, and didn't take precautions, and also didn't have the technology of today; resulted in that tragic day.