Having been in Washington, D.C., on that fateful September day, I personally witnessed the destruction of our Pentagon and the devastating impact that these brutal attacks had on our nation’s capital.

This was an unprovoked act of war designed and carried out by terrorists to weaken our nation and divide our people. They failed. In the wake of the tragedy, the American people came together with resolve to strengthen their conviction to our core American values — family, faith and country.

On Sept. 12, Congress led the nation in unity by singing “God Bless America” on the steps of the Capitol. Here in Los Angeles County, a multi-faith crowd of more than 2,500 gathered for an ecumenical prayer service held at the Kenneth Hahn Hall of Administration.

Many of the courageous and dedicated men and women of Los Angeles County’s law enforcement and public safety agencies traveled to the East Coast to help those in need. Many volunteered their time and energy to assist their colleagues in the clean-up and recovery effort.

Despite events that undoubtedly constituted one of our nation’s darkest moments, we were inspired by the generosity and selflessness many citizens showed their fellow Americans.

As time goes on and memories begin to fade, some question the validity of combating terror, even as the presence of those who would do us harm continues to grow and strengthen around the world.

We must never forget that more than 3,000 civilians, law enforcement and fire personnel lost their lives on Sept. 11, 2001. We must never forget that extremists are capable of repeating with similar attacks and that these terror networks are united by a common ideology of violence and hatred for freedom and American values.

The United States government and its allies must continue to fight against the extremist networks, organizations and individuals and their state and non-state supporters. We must remain vigilant in ensuring that the atrocities of 9/11 stay etched in our nation’s collective memory.

Three years ago, on the tenth anniversary of the 9/11 attacks, Los Angeles County declared Sept. 11 to be Patriot’s Day in remembrance of the thousands of innocent victims who perished years ago and to pay tribute to the brave men and women serving in our armed forces around the world in the global battle against terror.

We must remind future generations that our way of life exists under constant threat and that liberty must be defended whenever or wherever it is threatened. At a time when our country faced comparable peril, President Reagan asserted: “Freedom is never more than one generation away from extinction. … It must be fought for, protected and handed down for (our children) to do the same.”

On the 13th anniversary of the Sept. 11 attacks, let us remember the individuals who have perished in defense of freedom, and let us strive to honor their memories by ensuring the countless sacrifices they made have not been in vain.

5th District Supervisor Michael D. Antonovich is Mayor Pro Tem of the Los Angeles County Board of Supervisors.