Real air vent built into a bunker in Normandy. Grenade surprise! It lets in air, but not grenades.
Origin /r/interestingasfuck /u/WB25
Air vent in a bunker to redirect grenades back to the incoming troop https://lemmy.world/pictrs/image/245cb631-a0fe-4804-904f-b3ccfe19e38f.png
![](https://kbin.life/media/cache/resolve/entry_thumb/7a/60/7a601731e8b10a5aac567807f05113d5fba957b9fc9e4b65ec4cf5d9dc708fbd.jpg)