India, Sept. 11 -- Twenty years ago on this day (September 11, 2001), al-Qaeda terrorists hijacked four US passenger planes and crashed two of them into two New York skyscrapers and one into the Pentagon, killing nearly 3,000 people in the US. Led by Osama bin Laden, al-Qaeda planned the operation from Afghanistan, blaming the US and allied involvement for conflicts in the Muslim world.

Nineteen hijackers carried out the September 11 attacks, including 15 from Saudi Arabia. Out of the four, one plane crashed in a field in Pennsylvania after passengers tried to regain control of the plane and rushed the cockpit. The attacks claimed the lives of 2,977 people.

Thousands more were injured, while many others developed health problems linked ...