Ten years ago it was a fairly anonymous school in a suburb of Denver.

Today it’s a synonym for school horror, every parent’s worst nightmare.

Columbine.

It was a decade ago today that two troubled students, Dylan Klebold and Eric Harris, entered their high school armed to the teeth and seared the notion of a school rampage into the nation’s consciousness.

Before then parents for the most part sent their kids off confident they would return safe and sound at the end of the day.

Columbine changed all that. Before they turned their weapons on themselves, Klebold and Harris killed 12 classmates and a teacher, and wounded about two dozen others.

We have spent much of the past decade examining the idea of school security and how we can stop something like what happened at Columbine from ever happening again.

A lot of schools have installed metal detectors. There are now limits on what kind of backpacks students can use and how often they can go to their lockers. Doors that once swung open to invite just about anyone are now locked. Visitors must check in. Student and staff IDs now must be displayed. Disaster drills, one thought to be a relic of the Cold War, are once again in vogue.

None of it has stopped the possibility of a student – or anyone else – intent on violence carrying out their nefarious thoughts with horrific results.

We have witnessed even the most unlikely of locales – a one-room Amish schoolhouse – become a vision of unspeakable atrocity.

No one will ever hear the word Columbine again without school violence being refreshed in our memories.

A decade later, we’re still dealing with the aftermath.