Post 9/11 — Lessons to be learnt !!!

Its 9/11, cnn,bbc local channels all r foolding the mourning soul of US and this is 4 yrs since the tragedy. but the big question arises in mind has world any lesson from that attack or susequent WARS by US in the name of justice. most of the hell is created by US only now why dont US stops patronizing,giving help and making big hell even after killing their own people. I think nothing has been learnt after so many inoccent people have died from all the sides. and finally dont only mourn for the people of your own country !!!