Final answer:
Osama bin Laden was the leader of al-Qaeda, the group behind the 9/11 terrorist attacks. He masterminded the plan that led to nearly 3,000 deaths, which triggered the War on Terror and the US invasion of Afghanistan. Bin Laden was killed in 2011 by US Navy Seals.
Step-by-step explanation:
Osama bin Laden was the founder and leader of the extremist group al-Qaeda, responsible for the September 11, 2001, terrorist attacks. Bin Laden planned and financed the hijacking of four airliners that crashed into the World Trade Center, the Pentagon, and a field in Pennsylvania. This heinous act resulted in the death of nearly 3,000 people and prompted the United States, under President George W. Bush, to initiate the "War on Terror," which included the invasion of Afghanistan to dismantle al-Qaeda and remove the Taliban from power.
Despite the removal of the Taliban and disruption of al-Qaeda's activities in Afghanistan, bin Laden continued to evade capture and remained a central figure in promoting terrorism. He eventually was located in Pakistan, where he was killed by US Navy Seals in 2011 during the presidency of Barack Obama. The elimination of bin Laden was a significant event in the ongoing efforts to combat terrorism globally.