April 20, 1999, changed everything.

On that day, we watched as the unbelievable and the horrific happened at Columbine High School. The deaths of 12 students and one teacher changed everything about the way we educate and protect students.

Those of us with children changed the way we felt about them attending school. We wanted to rush to pick them up, and wondered whether they should be sent to school the next day. It changed the way we felt about the places we thought were as safe as our own homes.

It changed the way schools prepared for emergencies. Periodic fire drills aren’t enough. Now, schools practice lockout drills to keep people out of schools, and lockdown drills, where students and teachers lock classroom doors and hide under desks.

It changed the way schools are built. Now, architects design buildings that are easier to secure, harder to enter and full of security cameras from every angle. Larger schools are segmented so that one area can be contained from the others.

It changed the way police and fire departments react to an emergency. Various agencies can now communicate with each other, and it changed the process for entering a school to stop a perpetrator. It changed police weaponry, training and equipment.

It changed the way students are allowed to act at school. Bullying and intimidation are monitored and suppressed. Writings and art works are observed and judged for signs of potential trouble. A zero-tolerance policy for weapons means that Halloween costumes are limited, and butter knives and wooden drill rifles can be cause for expulsion.

In short, it changed everything.

Ten years later, we look back and hope that all this change has made our students safer, but mostly pray that the changes prove to be unnecessary, and that a Columbine never happens again.