FILE - Firefighters work beneath the destroyed mullions, the vertical struts which once faced the soaring outer walls of the World Trade Center towers, after a terrorist attack in New York, Sept. 11, 2001. The remains of two people who died in the 9/11 attack on the World Trade Center have been identified, the latest positive identification in the decadeslong effort to return victims to their families. Authorities confirmed the identification of the remains of a man and woman days ahead of the 22nd anniversary of the hijacked-plane attack that killed nearly 3,000 people in Lower Manhattan. AP

FILE An American flag is unfurled at the Pentagon, in Washington, Sept. 11, 2021, at sunrise on the morning of the 20th anniversary of the terrorist attacks. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

FILE The twin reflecting pools, center, of the National September 11 Memorial are illuminated during the evening, April 1, 2012, at the World Trade Center, in New York. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

FILE Identical twins Janita Ollison, left ,and Jeannetta Ollison 17, of Gresham Oregon, try to read some of the names of 9/11 victims printed on more than twenty -six hundred Flags of Honor erected as a memorial to represent each person killed by terrorist attacks, Sept. 11, 2001 in Gresham Ore., Wednesday, Sept. 10, 2003. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

FILE Hundreds of American flags surround a memorial to the victims of the Sept. 11 terrorist attacks, behind Eastlake, Ohio, City Hall, Sept. 6, 2002. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

FILE First responders work at ground zero after the Sept.11 attacks, Sept. 12, 2001, in New York. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

FILE An American flag flies from a makeshift altar overlooking the ongoing investigation of the United Flight 93 crash site, in Shanksville, Pa., Sept. 16, 2001. Americans are looking back on the horror and legacy of 9/11, gathering Monday, Sept. 11, 2023, at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

A man walks past American flags and flowers lining the memorial pool at the National September 11 Memorial to mark the 22nd anniversary of the 9/11 terror attack at the World Trade Center on September 11, 2023 in New York. AFP

A rose is placed on a bench at the National 9/11 Pentagon Memorial during a ceremony observing the 9/11 terrorist attacks at the Pentagon on September 11, 2023 in Arlington, Virginia. The Defense Department held a remembrance ceremony for the 184 lives lost in the 2001 terrorist attack on the Pentagon. Today marks the 22nd anniversary of September 11, 2001 terrorist attacks at the World Trade Center, the Pentagon and Shanksville, Pennsylvania. AFP

Family members of victims attend a ceremony observing the 9/11 terrorist attacks at the Pentagon on September 11, 2023 in Arlington, Virginia. The Defense Department held a remembrance ceremony for the 184 lives lost in the 2001 terrorist attack on the Pentagon. Today marks the 22nd anniversary of September 11, 2001 terrorist attacks at the World Trade Center, the Pentagon and Shanksville, Pennsylvania. AFP

A family member brings flowers at the National 9/11 Pentagon Memorial to honor the 184 people killed in the September 11, 2001 terrorist attack on the Pentagon, in Washington, DC, on September 11, 2023. AFP

A man takes a photograph at the National 9/11 Pentagon Memorial on the 22nd anniversary of the September 11, 2001 terrorist attack on the Pentagon, in Washington, DC, on September 11, 2023. AFP

A person looks at flags before the commemoration ceremony of the Sept. 11, 2001, terror attacks, Monday, Sept. 11, 2023, in New York. Americans are looking back on the horror and legacy of 9/11, gathering Monday at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP

People carrying a wreath arrive at the commemoration ceremony of the Sept. 11, 2001, terror attacks, Monday, Sept. 11, 2023, in New York. Americans are looking back on the horror and legacy of 9/11, gathering Monday at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. AP