There are some things that happen during flights that you just take for granted, like plane lights being dimmed for takeoff.
But the reason behind this very thing happening is actually interesting.
The Telegraph has uncovered the reason is really all about keeping everyone safe.
"Dimming the lights allows your eyes to pre-adjust to darkness, so that you're not suddenly blinded if something happens and the power goes out, and you're dashing for the doors in darkness or smoke," Patrick Smith, an airline pilot and author of Cockpit Confidential tells The Telegraph.
"The emergency path-lighting and signs will also be more visible," he continues. "And it makes it easier to see outside, which helps you to maintain at least a basic sense of orientation — i.e. which way is up."
That's a fun fact to keep in mind for next time your flying!