Why did the Columbine shooting happen?

It's hard to say, but there's evidence of the two shooters at Columbine, Dylan Klebold and Eric Harris, being bullied on a daily basis. Many say that this made them snap and plan to take it out on the school that they hated so much.

Also, if you take the time to read (or read about) their journals, they wrote entry after entry of incredibly angry rants. They hated mankind and thought that they were more evolved or more enlightened than everyone else around them.

They didn't really kill anyone in particular at Columbine... They just wanted to achieve a high body count.

The bottom line is that they were disturbed kids who were treated poorly and hated humanity. They didn't just one day snap...they'd had this massacre planned for well over a year. i agree they planned it for over 12 months and they planned it pretty well to bad that they did what they did they could have been very successful in life