Flying is basically an essential nowadays. If you want to travel quickly and efficiently (and avoid hours in the car), getting on a plane is your best and sometimes only option. But, despite how normalized flying has become, that doesn’t necessarily mean you know anything about the aircraft that’s taking you from Point A to Point B.

Planes are incredible — albeit often scary — pieces of machinery and very few people realize that they’re constructed to do some pretty fascinating things. Besides the obvious task of flying humans through the air at unbelievable speeds, of course.

From the holes in the wings to the hidden plane beds, here are seven airplane secrets that no one knows.

1. Airplanes Can Withstand a Lightning Strike

Taking flight during a scary storm isn’t a pleasant thought, but this is a comforting notion: airplanes are designed to withstand lightning strikes. Thanks to extremely precise engineering, a bolt can pass safely through a plane without causing any damage.

Don’t worry, this engineering has been put to the test — more than you’d think, actually. Planes are struck by lightning once for every 1,000 hours of flight. That comes out to about once a year.

And the last time a plane was brought down by a bolt of lightning? 1963.

2. There’s a Secret Bedroom

Flight attendants often work up to 16-hour days, flying in and out of various time zones. Needless to say, they need some rest!

Just for this purpose, some planes that do long-haul trips will be equipped with a bedroom. These hidden nooks are usually slightly below deck and can be accessed by a short, spiral staircase.

Some of them even have in-flight entertainment for the unsung heroes of the sky!

3. Those Yellow Masks Have Just Enough Oxygen

Seeing oxygen masks drop down is obviously a scary sight. Here’s something even scarier: there’s only 15 minutes worth of oxygen in each mask.

But the amazing thing is that this is actually more than enough flowing air.

The reason these masks come out is because the pressure in the airplane cabin is changing, making it difficult for us to breathe. However, in these situations, pilots bring the plane down below 10,000 feet, where humans can easily draw breath.

Taking the plane down to 10,000 feet only takes a few minutes, so the 15 minutes is actually way more than we actually need.

To learn the other four airplane secrets (like where the safest seat on the plane can be found) make sure to watch the video!