21st Anniversary of 9/11 Terror Attacks in Photos

First responders salute as a U.S. flag is unfurled at the Pentagon in Washington, Sept. 11, 2022, at sunrise on the morning of the 21st anniversary of the 9/11 terrorist attacks.

President Joe Biden participates in a wreath laying ceremony while visiting the Pentagon in Washington, Sept. 11, 2022, to honor and remember the victims of the September 11th terror attack.

A bell is rung during a ceremony at the Pentagon in Washington, Sept. 11, 2022, to honor and remember the victims of the 9/11 terror attack.

Family members attend a ceremony at the Pentagon in Washington, Sept. 11, 2022, to honor and remember the victims of the 9/11 terror attack.

A visitor looks at the Wall of Names before a ceremony commemorating the 21st anniversary of the Sept. 11, 2001 terrorist attacks at the Flight 93 National Memorial in Shanksville, Pennsylvania, Sept. 11, 2022.

U.S. Vice President Kamala Harris and Second Gentleman Doug Emhoff walk through the 9/11 Memorial in New York City, Sept. 11, 2022

Names of victims are read during a remembrance ceremony at the 9/11 Memorial in New York City, Sept. 11, 2022, on the 21st anniversary of the attacks on the World Trade Center, Pentagon, and Shanksville, Pennsylvania.

A member of the New York Fire Department salutes during a remembrance ceremony at the 9/11 Memorial in New York City, Sept. 11, 2022

Members of New York Fire Department raise a U.S. flag at the 9/11 Memorial in New York City, Sept. 11, 2022

A relative of a victim holds an image and flowers at the 9/11 Memorial in New York City, Sept. 11, 2022.

Relatives of the victims look at the 9/11 Memorial in New York City, Sept. 11, 2022, on the 21st anniversary of the attacks.

People observe a moment of silence on Cedar Street by the perimeter of the commemoration ceremony of the 9/11 terror attacks, in New York, Sept. 1, 2022.

A relative of a victim places U.S. flags on the 9/11 Memorial in New York City, Sept. 11, 2022

A woman reacts during a ceremony marking the 21st anniversary of the September 11, 2001 attacks on the World Trade Center at the 9/11 Memorial and Museum in the Manhattan borough of New York City, Sept. 11, 2022.

Flags and flowers are placed at the 9/11 Memorial and Museum during a ceremony marking the 21st anniversary of the September 11, 2001 attacks on the World Trade Center, in the Manhattan borough of New York City, Sept. 11, 2022.

Colonel Davis attends a ceremony marking the 21st anniversary of the September 11, 2001 attacks on the World Trade Center at the 9/11 Memorial and Museum in the Manhattan borough of New York City, Sept. 11, 2022.

A general view shows the 'Tribute in Light' installation amid the Manhattan city skyline commemorating the 9/11 terrorist attacks, in New York, Sept. 10, 2022.