When school administrators hear that the 10th anniversary of the Columbine High School attack is approaching, most shake their heads in disbelief. They are amazed that 10 years have passed since this watershed event, which changed the landscape of K-12 school safety. In this article, the author reflects on the lessons learned from the Columbine attack, and how these lessons have resulted in substantial changes in the safety of the nation's schools. He concludes that, although schools in general are more secure and better prepared for emergencies today than they were prior to the Columbine attack, glaring gaps in prevention, security, and preparedness remain.