Nearly 3,000 people were killed in the attacks, which prompted President George W. Bush to declare a "war on terror".

The US-led coalition forces then launched attacks on Afghanistan to topple the Taliban regime, which was sheltering the Al-Qaeda leadership.

The Taliban were ousted from power, but were not defeated. In the last eight years, the Taliban have, in fact, regrouped, indicating that an end to the conflict is hardly in sight.