It has been 25 years since the Sept. 11, 2001, attacks. It’s hard to believe that something so significant is now a quarter century old. In fact, it is estimated that nearly a third, or 100 million Americans, are too young or were not born to remember how significant that day was for the United States.

The rest of us who cannot forget the horror of that day, or the wars and governmental changes that came after it, have an obligation to not only remember but to teach the next generation. To date the Sept. 11 attack is the deadliest terrorist attack in U.S. history. We need to remind our children and grandchildren that 2,996 men, women and children were killed that day, including 19 hijackers who flew the four commercial airliners. They must learn from us and be ever vigilant if they are to try and prevent another large-scale attack on U.S. soil.

Twenty-five years later, we need to remember that the majority of those killed were civilians — innocent victims going about their lives much like each of us do every day. They had no choice when their lives were cut short. Their absence left a huge hole in the hearts of their friends and loved ones that still haunt their families today. We know the final thoughts of some of them. In the years that have passed many of their final cellphone calls and messages have been released … including those from passengers on Flight 93 who rushed to the cockpit, causing the airplane to crash near Shanksville, Pa., rather than allowing it to hit another target. It could have been any one of us.

Equally important, we need to remember those who had a choice, our first responders who rushed into burning and collapsing buildings, who triaged the wounded and worked tirelessly for days looking for survivors. 441 first responders perished on 9/11. 343 members of the New York City Fire Department and one New York Fire Patrolman died. The rest were law enforcement officers, Port Authority officers, paramedics and other medical personnel who gave their lives to save others. Their efforts were herculean. We now know that nearly all the deaths in the twin towers, for example, occurred on the floors where they were trapped by the planes’ impacts. These first responders risked their lives to rescue as many of them as they could. Phones failed, doors jammed, shafts were full of flames and smoke, radios were overwhelmed and yet our brave first responders went in.

We must also remember the sacrifice and service of our brave military men and women who embarked on what would be called the Global War on Terror. They would deploy to Afghanistan, Iraq and other locations for nearly 20 years. Nearly 3 million U.S. service members deployed abroad because of these attacks, many multiple times, while 7,074 service members would die and tens of thousands were wounded, not to mention those with PTSD and TBI still impacting them today. Sadder still is that over 30,177 U.S. service members and veterans of the war on terror have died by suicide since Sept. 11, 2001.

Twenty-five years later we must also remember that nearly 1,500 people, who lived and worked in lower Manhattan at the time of the attacks, have been diagnosed with some form of cancer that has been attributed to toxic exposure from the explosions, fires and dust at ground zero. An additional 1,600 first responders who were on the scene have also died since the attacks. Still, those of us alive at the time remember hearing that it could have been much worse. On most days, later in the day, nearly 19,000 people worked in or visited the twin towers.

There was also a fiscal cost to our country. Charities raised over $657 million in just the three weeks following the attacks for survivors and victims’ families. It is estimated that the attacks cost the United States $3.3 trillion including physical damage, economic impact, homeland security costs, war funding and future war and veteran’s care. Most estimates are that the al-Qaida terrorists spent about $500,000 planning and training for the attack, most of that being flight training.

This year, take a moment to remember the day that so many would rather forget. Every year since the attacks it has become more noticeable that many have a business-as-usual approach to the day, with events and business happening as they do on any other day. It is up to us to remember and to teach the next generation why Sept. 11 is known as Patriot Day. To not remember is to dishonor all those who died and sacrificed as a result. Our world feels far less secure than it was 25 years ago and to not remember is also to condemn a future generation to a similar fate.

Dan Williams is the district 1 Teller County commissioner and a retired US Army active-duty combat veteran who fought in Iraq and Afghanistan in the Global War on Terror.