What caused september 11th attack?
Muslim fanatics attacked the US because of their belief that predominantly Christian nations such as the US have deprived the Islamic world of the leading role, and the power and prestige that it rightfully deserves. Christianity and Islam have been in conflict since the Crusades (beginning in the year 1000) and US support for the nation of Israel since 1948 has greatly inflamed Muslim resentment toward the US. To the September 11th terrorists, that attack was merely the latest battle in a long running war between faiths.
