EXPLAINER: Who was al-Zawahri -- and why did US kill him?

A U.S. drone strike in Afghanistan this weekend killed Ayman al-Zawahri, who helped Osama bin Laden plot the Sept. 11, 2001, attacks on the United States and ensured al-Qaida survived and spread in the years after. President Joe Biden on Monday announced the killing of al-Zawahri, delivering a significant counterterrorism win just 11 months after American troops left the country. A look at the al-Qaida leader, who evaded U.S. capture for 21 years after the suicide airliner attacks that in many ways changed America and its relations with the rest of the world. Americans who lived through the 9/11 attacks may not remember al-Zawahri's name, but many know his face more than two decades on: a man in glasses, slightly smiling, invariably shown in photos by the side of bin Laden as the two arranged the strike on the United States. An Egyptian, al-Zawahri was born June 19, 1951, to a comfortable family in a leafy, drowsy Cairo suburb.