22. The Colombine Hero
The mass murder at Colombine High School in 1999 was one of the saddest moments in American history. The shooters took the lives of 12 students and a teacher. Another 24 people were also injured and have to live with those terrifying moments for the rest of their lives.
The one shining light was teacher Dave Sanders. He ran into the cafeteria to warn students about the shooters. His efforts potentially saved dozens of lives. Sadly, Sanders ran into the shooters after that. They shot him twice and left him for dead. Sanders will always be remembered for his heroic efforts.