world and the humanlife

Since the evolution of man ,he has been waging all kinds of war.He has been fighting for food, land ,rights and evenwives.Almost all the countries have faced war with external forces or from with in the form of civil war.No one in his right senses would prefer war to peace,but there always will be warmongers and despots out for somebody's blood and life.But most of the time,man has lived in peace and harmony with his nighbours.
Now a days ,some people are waging a different kinds of war .On the 1th of september 2001,some terrorists hijacked four planes and crashed them in the twin towers of the World Trade Centres and Prntsgonr.killing thousands of innocent civilian working in those places This act was describedby the president Bush.
so,what are the results that these terrorists are trying to achive by killing innocent civilians who have nothing to do with their fight, If this form violence is cpnsidered a fight at all