Short answers, pulled from the story.
The war on terror, officially the Global War on Terrorism, is a global military campaign initiated by the United States in response to the September 11 attacks in 2001. Its main targets were militant Islamist movements such as al-Qaeda, the Taliban, and their allies.
George W. Bush first used the phrase war on terrorism on the 16th of September 2001 at Camp David, in an ostensibly unscripted comment. He used war on terror a few days later, on the 20th of September 2001, in a formal speech to a joint session of Congress.
A total of 2,977 victims and the 19 hijackers died in the September 11 attacks. Fifteen of the nineteen hijackers were citizens of Saudi Arabia, with the others from the United Arab Emirates, Egypt, and Lebanon.
According to the Costs of War Project, the post-9/11 wars have displaced 38 million people and caused more than 4.5 million direct and indirect deaths across Afghanistan, Iraq, Libya, Pakistan, Somalia, Syria, and Yemen. The same project estimates the campaign has cost the US Treasury over 8 trillion dollars.
Controversy focused on the war's morality, casualties, and continuity, with critics questioning measures that infringed civil liberties and human rights. Condemned practices included drone warfare, surveillance, torture, extraordinary rendition, and the expansion of government surveillance powers under the USA PATRIOT Act, which critics called Orwellian.
The war in Afghanistan ended on the 15th of August 2021, when Kabul fell to a swift Taliban offensive. The United States completed its hasty military withdrawal on the 30th of August 2021, after evacuating over 120,000 people.
Osama bin Laden, his wife, and his son were killed on the 2nd of May 2011, during a raid conducted by United States special operations forces in Abbottabad, Pakistan.