11 September 2001,
Two aircraft faced the attack on the Twin Towers of the World Trade Center in New York. Four Al-Qaeda teams took as hostages an aircraft that was going to carry out long, fuel-laden flights. The attack caused 2,973 deaths and $80 billion, a third plane hit the Pentagon and the fourth failed for passenger resistance.
19 people caused more damage and casualties to the United States than the Japanese attacks of Pearl Harbour in 1941.
Source:
Josep Fontana, for the sake of empire. (Ed. Past tense).