Monday marks the 22nd anniversary of the 9/11 terror attacks — the deadliest such attack on U.S. soil — which took the lives of nearly 3,000 people.

A group of 19 terrorists tied to the Islamic extremist group al-Qaeda targeted buildings in New York and Washington, D.C., with hijacked planes. More than 400 first responders were killed in the collapse of the twin towers at the World Trade Center in New York and its aftermath.

Every year, the nation honors the lives lost at New York's ground zero, the 184 people who died in the attack on the Pentagon and those in Shanksville, Pennsylvania, where an aircraft crashed after passengers successfully overtook the terrorists during the flight.

Here's a look at how the country is commemorating the tragic day.

A jogger carries the American flag along the National Mall

First responders watch as a U.S. flag is unfurled outside the Pentagon

Secretary of Defense Lloyd Austin lays a wreath during a ceremony at the Pentagon

Family members of a victim visit the Pentagon Memorial

A member of the military attends services at the National September 11 Memorial in New York

New York firefighters observe a moment of silence

First responders hold a U.S. flag during the bell-ringing ceremony at ground zero

Mayor Eric Adams and Vice President Kamala Harris attend the remembrance ceremony in New York

Former New York Mayor Rudy Giuliani attends the ceremony

Visitors stroll through the national park grounds in Shanksville PA

A relative of one of the victims pays her respects at the Wall of Names commemorating the 22nd anniversary of the crash of Flight 93

American flags fly at half-staff around the Washington Monument on the National Mall

Victim's names are seen in a program during a ceremony at the Pentagon