9/11 attack plan

  World Trade Centre attack in 2001

On September 11, 2001, 19 hijackers took control of four airplanes and were targeting The World Trade Center in New York, The Pentagon near Washington, D.C., and the United States Capitol Building. Two planes hit the World Trade Center. One hit the Pentagon, however one plane never arrived at its target, the Capitol Building. Almost 3,000 people died, making it the most deadly terrorist attack in U.S. History. It was carefully planned by Al-Qaeda, who sent 19 terrorists to take over Boeing 757 and Boeing 767 aircrafts, operated by American Airlines and United Airlines.
As of February 2010, Al-Qaeda "was allegedly contemplating conducting an operation against trains at an unspecified location in the United States on the 10th anniversary of September 11, 2001," the US Department of Homeland Security (DHS) advised law enforcement agencies in a bulletin obtained by AFP.
A source said the warning arose from intelligence seized in a daring raid on bin Laden's fortified compound in which elite US commandos shot dead the terrorist mastermind and gathered computer hardware and other material.

The official message noted that it was based on "initial reporting" and warned that such information "is often misleading or inaccurate due to a rapidly developing situation and is subject to change."
Al-Qaeda "was looking into trying to tip a train by tampering with the rails so that the train would fall off the track at either a valley or a bridge," according to the department.
"While it is clear there was some level of planning, we have no recent information to indicate an active ongoing plot to target transportation and no information on possible locations or specific targets," the bulletin said.