(Sept. 11, 2001)

Two planes crashes into twin towers of World Trade center in New York

    Twin towers of World Trade center in New York collapsed over one hour after two planes crashed into them around 9 a.m. on Sept. 11, 2001.

    U.S. President George W. Bush said that the crashes were "an apparent terrorist attack on our country," and ordered a full-scale investigation to "hunt down the folks who committed the act."

    One of the planes that crashed into the World Trade Center had been hijacked after takeoff from Boston, a U.S. official said, citing a transmission from the plane.

    All planes were grounded across the country by the Federal Aviation Administration. All bridges and tunnels into Manhattan were closed down.

    Several subway lines were immediately shut down. Trading on Wall Street was suspended.

    Large holes were visible in sides of the 110-story buildings, landmark twin towers. Dense smoke billowed far into the sky above the gaping holes in the side of the 110 story twin towers and debris pelted down upon street, one of the city's booming work areas. When the second plane hit, a fire ball of flame and smoke erupted, leaving a huge hole in the glass and steel tower.

    People ran down the stairs in panic and fled the building. Thousands of pieces of possibly office paper came drifting over Brooklyn, about three miles away.

    Terrorist bombers struck the World Trade Center in February 1993, killing six people and injuring more than 1,000 others.

Aircraft crashes into Pentagon

    An aircraft crashed into the Pentagon on Sept. 11, 2001 and the West Wing of the White House was evacuated amid threats of terrorism.

    Reports said that the tail-end of a large airliner plunged into the building and smoke billowed out of the Pentagon.

    An American Airlines flight from Washington to Los Angeles crashed into the Pentagon with 64 passengers and crew aboard. The fuel-laden jet, which had just taken off from Washington's Dulles Airport, set the world's largest office building ablaze and forced thousands of employees to evacuate.
 
    The attack occurred shortly after two other commercial jetliners were hijacked and flown into the twin towers of the World Trade Center in New York. A fourth plane that was hijacked crashed in a wooded area in Pennsylvania.
 
    The Pentagon suffered widespread damage on its the building's fourth, fifth and sixth corridors, and the impact tore a gaping hole in one side of the building.    
Major attacks on US targets in recent years

    Following are the terrorist attacks on US targets in recent years, including one happened in the World Trade Center on February 26, 1993, when a bomb exploded in a parking area below the towers, killing six people and wounding more than 1,000. In the case, six Islamic militants were convicted in the bombing and sentenced to life in prison:

    -- October 12, 2000: Terrorist bombing kills 17 US sailors aboard the USS Cole as it docked at Yemen's port of Aden.

    -- August 7, 1998: Car bombs explode outside US embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, killing 224 people and wounding thousands of others.

    -- June 25, 1996: Truck-bomb explodes outside the Khobar Towers, Dharan, eastern Saudi Arabia, killing 19 American servicemen and wounding hundreds of various nationalities.

    -- September 13, 1995: Rocket-propelled grenade pierces wall of US Embassy in Moscow, but causes no injuries.

    -- November 13, 1995: Car bomb detonates at a US military headquarters in Riyadh, Saudi Arabia, killing five American service personnel.

    -- April 19, 1995: Bomb rips through the Alfred P. Murrah Federal Building in Oklahoma City, killing 168 and wounding more than 500. Former U.S. soldier Timothy McVeigh is convicted of carrying out the attack, who was executed earlier this year.

    -- December 21, 1994: Explosion wounds 45 people on a subway train at a station near the World Trade Center in New York.