[Tangram]

I live in the US. In elementary and middle school, gender segregation was a big thing. Most of the buses I rode on were either segregated by side or at least by seat. About half of the years I was in school, lunch was the same way. I've never been in a PE class where boys and girls played together (unless it was free time recess, outside). High school field trips were pretty often segregated, on the bus, out to eat, at amusement parks, etc.

I've been to concerts where there are sections where only girls can go, and the rest is free-for-all. That's for the protection of the girls who aren't totally comfortable being lost in a crowd of guys. I couldn't imagine why concerts would be totally segregated though.