To let a breeze into your room, do your windows open out from the bottom or the top?
If your windows are stacked (upper and lower) which part opens and which part stays fixed?
(Germans with 3D windows don’t count. Lüften is a weird cultish ritual and you should all feel bad.)
Screens for keeping bugs out!
But I couldn’t walk through a door-sized version if there were a screen, unless there’s some other European magic I didn’t know about.