People Are Learning Why There's A Tiny Black Triangle Above Plane Windows

You may already know the real reason flight attendants greet you when you come on board, or what’s actually going on when you’re barred from returning to the plane when you’ve left something behind. 

But if you’ve ever noticed some mysterious black triangles above certain plain windows, they might have left you stumped. 

Luckily, people like u/altrightobserver over on Reddit’s  Read Entire Article