Well I guess a couple of things stood out during my time in high school. I live near a part of the Netherlands that, well, is known for it's socio-economic challenges, a lot of the stuff that happened could probably be related to that. A few examples:
1) A chinese girl from my senior year group committed suicide, sad story really. Apparently she was under a lot of pressure to perform well in school, but she didn't. She hung herself from the curtain rails with the curtains being shut. As the story goes, her little brother found her after he went looking for her in the house, and to his horror only found her when he tried to pull the curtains aside to see if she was in the yard outside. I didn't know her too well, but she was like the best friend of a female friend of me at that time. The entire school was in uproar; teachers sitting outside crying, social workers trying to talk to us, group sessions.. It all ended pretty sudden when we attended her funeral a few days after.
2) Mass fights would often break out at my high school during recess, mostly between some skaters (stoners you guys would call them) and some moroccan youth. You'd best get out of the way when that happened, as sometimes these guys would bring knives. Because of this, the police would often patrol around our school at recess.
3) My german teacher died of cancer in what felt like weeks. I remember having German class with him, then all of a sudden he would disappear for weeks and we would get a substitute. Then the substitute was gone and he returned, and just a week after that I came into school on monday to see everyone around us sobbing and crying, and seeing a little shrine with a picture of the guy smiling and a single candle placed in front of it. Such a weird vibe...
4) I was mugged in broad daylight while having a walk around the school premises with a friend of mine, I was probably around 12 years old. The guy had a knife and was threatening to cut us up if we didn't pay up. All he got was a whopping two or three guilders (the dutch currency at the time).
5) And to end on a lighter note: when you finish high school in the Netherlands, a school dance or prom is often organised near the end of the senior year. Ofcourse we had one as well. I remember a lot of booze being smuggled in, by both teachers and students. A lot of the teachers were piss drunk, one would take off his shirt while dancing and being in this weird liquor induced delirium, we laughed our asses off. Also, our janitor yelled "Everybody's gonna get laid tonight, bitches!!" just before the dance started, which made us feel slightly uncomfortable, lol! Ofcourse, nobody did get laid, but still, it was funny at the time.