The Columbine High School massacre shocked the nation on Tuesday, April 20, 1999. Two high school seniors, Eric Harris and Dylan Klobold, planned a brutal attack on their high school after months of preparing and planning. Much of their plans did not succeed, and yet they killed 12 students, one teacher and injured several others.

Harris and Klobold had a history of criminal and emotional issues and were being monitored by local law enforcement. They had created their own website and kept a blog, which chronologued their unhappiness and anger with society. Posts on their website contained death threats filled with hate and violence. The growing anger on the website was noticeable and their discussions included talk of building up arms and bombs. They specifically listed their increasing gun count and named individuals that they wished to target because they bothered them.

Harris had complained of depression, suicidal thoughts, and increasing anger and we put on medication. At the time of his death he had therapeutic levels of antidepressants in his system. Unfortunately, some people believe that these medications may have increased his aggression and mania.

Harris and Klobold videoed much of their plans while preparing for this massacre. Between journal entries, blog posts, and videos, there was little left unsaid. They boasted of how they illegally obtained their weapons and explosives and how they cleverly hid it in their homes. Their plan called for a several bombs in the school creating more damage than the Oklahoma City bombing, their escape to Mexico, and hijacking of a plane and crashing it into a building in New York City.

In their last recorded video, about 30 minutes before their attack, the boys apologized to their family and friends and said their final goodbye.

That day,they boys arrived at the school at 11:10. The first bomb was set to explode at 11:14 a half a mile away from the school to divert emergency personnel. The bomb partially went off, but the fire department was able to put out the fire with ease.

The boys placed two duffel bags with explosives inside into the cafeteria. These bombs were set to explode at 11:17. The boys positioned themselves outside the cafeteria, where they were prepared to shoot students as they ran from the inside explosions. When the bombs failed to explode they began walking to the cafeteria.

At 11:19 they shot two students sitting outside. One person was shot four times and the other person was shot eight times. After this, the plan was over and the shooting was random. They threw several pipe bombs which did not detonate. A police sheriff arrived at the scene by 11:24 and began shooting at Harris and Klobold. The boys escaped into the building and continued shooting anyone in their path.

At 11:29 they entered the library yelling directly at their fellow students and shooting several of them. They reloaded their weapons and began shooting out the window at the police surrounding the building. They left the library at 11:42.

From the library, the boys walked the halls and taunted anyone in their paths. By 12:08 they turned their guns on themselves and ended the massacre.

During the aftermath of the shootings, the only question left unanswered was the cause. The two boys were considered very bright but socially unaccepted. Bullying was tagged as one possible cause along with violent video games, antidepressants, and goth culture tagged as other possible causes.