Why the twin towers were attacked?

Answer 1

All of the fatwas, before September 11, 2001, from Osama bin Laden have a consistent theme : US troop presence in Saudi Arabia. In 1998, bin Laden said in a fatwa: "For more than seven years the United States has been occupying the lands of Islam in the holiest of places, the Arabian peninsula, plundering its riches, dictating to its rulers, humiliating its people, terrorizing its neighbors, and turning its bases in the peninsula into a spearhead through which to fight the neighboring Muslim peoples" (see February 22, 1998). [Nation, 2/15/1999] The attacks were consistent with the overall mission statement of al-Qaeda, as set out in a 1998 fatwā issued by Osama bin Laden, Ayman al-Zawahiri, Ahmed Refai Taha, Mir Hamzah, and Fazlur Rahman.

This statement begins by quoting the Koran as saying, "slay the pagans wherever ye find them" and extrapolates this to conclude that it is the "duty of every Muslim" to "kill Americans anywhere".[125] Bin Laden elaborated on this theme in his "Letter to America" of October 2002: "You are the worst civilization witnessed by the history of mankind: You are the nation who, rather than ruling by the Shariah of Allah in its Constitution and Laws, choose to invent your own laws as you will and desire. You separate religion from your policies, contradicting the pure nature which affirms Absolute Authority to the Lord and your Creator."