The tragedy at Columbine has changed not only history, but the future of how law enforcement handles shootings with mass causalities.
Local law enforcement agencies have changed response and training tactics.
An official with the Grand Junction Police Department says the state, the nation, and the world learned from that day and changed their tactics after seeing the flaws of Columbine.
On the day of the shootings, law enforcement officers secured the outside of the school, but waited 45 minutes for the swat team to arrive before going into the school.
During that time, ten of the thirteen were killed.
Officials say Columbine sparked the "active shooter" tactic: now, officers don't wait to secure a location, but instead, make immediate entry to stop a shooter.
They also train on campuses, becoming familiar with layouts, locked and unlocked doors, and how to get access to different areas.
Schools are also now assigned 'Resource Officers', an on–campus officer who specializes in the ins and the outs of that school, and teachers and faculty have undergone new training, like lockdowns drills with students.
Officials say the incident, although tragic, will hopefully help first responders better prepare for the worst should history ever repeat that horrible day.