Sept. 11, 2001.

This is perhaps one of the most infamous dates in modern American history. It needs no explanation. Just reading that date, you remember what happened. You probably remember where you were, what you were doing and exactly how you felt when you heard the news.

You don’t need a newspaper to remind you of the events of that day and the repercussions that followed. Surely you haven’t forgotten the terrible images on TV and the acts of heroism that followed on the part of first responders. After all, how many of us promised that we would never forget that day?

Seeking retribution against the ones responsible for the attacks, the United States invaded Afghanistan less than a month later, on Oct. 7, 2001. It was the precursor to war. This year, for the first time, U.S. soldiers who were not even born on 9/11 may be deployed to fight the continuation of that war.

Also in October 2001, President George W. Bush signed into law a piece of legislation meant to give federal agencies the tools they needed to combat terrorism. What followed, however, was an unprecedented expansion of government surveillance, not just on terror suspects, but also on average American citizens.

One of the few silver linings of that dark day, however, is that it was also a time of unity for Americans. On that day we put aside partisan politics, political ideologies and the socioeconomic dividers that so often divide us. We weren’t Democrats or Republicans, black and white, rich and poor — we were Americans, and we cared about each other.

Of the lessons of 9/11, from the frightening longevity of war to the dangers of government overreach, the unity we felt on that day and in the days after is something that we need today more than ever. Eighteen years after 9/11, we seem more divided as a country than we have ever been.

Take a moment today to reflect on 9/11. Think about the lives lost, not just on that day, but in the years that followed. Give some consideration to how that one event fundamentally altered the country, in some ways for the better and in some ways for the worse. Think about how that day brought people together and brought out the best in our country, and how in the depths of our current divisions, we might find some semblance of that unity once again.

Today, remember Sept. 11, 2001, and what it has meant for our country.