Obama, Queen Elizabeth, U.S. senators remember 9/11

U.S. former President Barack Obama, former First Lady Michelle Obama, President Joe Bien, First Lady Jill Biden, former New York City Mayor Michael Bloomberg attend the annual September 11 Commemoration Ceremony at the National 9/11 Memorial and Museum September 11, 2021 in New York City, U.S., September 11, 2021. Chip Somodevilla/Pool via REUTERS

WASHINGTON (Reuters) -Former presidents, world leaders and U.S. lawmakers reflect on the 20th anniversary of the Sept. 11 attacks on the United States.

BILL CLINTON, 42nd U.S. PRESIDENT