School shootings in the USA (Columbine's Massacre)

Coming back from hiding in
 an alley behind the school

Students and teachers freed from the staff
 lounge & cafeteria restrooms run from Columbine

1. the information that you find most interesting on this site. Express your preferences in your own words, please.

On April 20, 1999, during lunch time at Columbine High Scoool; Eric Harries and Dylan Klebold, two students, came to school armed with shotguns and assault rifles. They walked through the school firing randomly at other students and teachers. Before killing themselvves in the school's library.

This sad event had changed drastically the life of students, teacher and parents. 

Dylan Klebold & Eric Harries

But who were the shooters ? Eric Harris and Dylan Klebold, were two seniors from Columbine School in Colorado. They were a few days away from their graduation day when they decided to commit the shooting. The Memorial website offers the viewers the opportunity to read the diaries of both Dylan and Eric. As it was to expect, these two diaries are full of hateful thought and messages to their classe mates.

Dylan manages to partially-detonate
 one propane bomb, causing a fire

Here we have fotos of friends, kids, and families that had a loved on in the Columbine High school, after the massacre. We can see the look on their faces; they look sad, broken, desperate after the news

2. 

The school shooter, Tate, in AHS

I think that one of the series that best deals with this issue is American Horror Story (AHS), and more precisely season one
One of the main characters in this season is a school shooter who killed 15 people. The writers of the show used a real internet search page in one episode where they edited "Columbine" to read "Westfield" but the rest of the search results obviously reference the Columbine shooting. The subject of the shooting reappears several times throughout the season. Aired in 2011.
What really happened in this episode? Tate (the man in the photo), has a flashback to when he was a student, in 1994, in Westfield High School. He menacingly stalked his classmates in the library until he shot dead 15 of his classmate, and permanently handicapped the school librarian. After the massacre, the "Wolverines Memorial Trust" was started in memory of the students. After the shooting, the SWAT team swarmed his house, and while his mother, Constance, cried in agony, they gunned down Tate in his room.
This episode looks quite alike what happened in real life. The shooters first stalked their classmates. The act that made the biggest number of damages was when they were in the librairie. They ended up dead.

 3.  the reasons most commonly mentioned for the recurrence of school shootings in the USA.

In the website, it is explained that school shooting happen mostly because of bullling ("They want to get back at those who have hurt them", "Other kids pick on them, make fun of them or bully them", "They have been victims of physical abuse at home"). Even though Dylan and Eric were pushed to commit this crime because of the bullying they've been victims of for years. I believe that the main reason school shooting happen is because they probably have mental problem, or more importantly it is because it is easy for them to get a gun. Which mean that the main side of the question should be around the gun issue.

Sadly, school shooting are very common in the United States. There are at least one school shooting per week. This sad fact should wake up those Americans that are pro guns. Because they are literally sending their kids in the arms of death.