Round airplane windows may make for cool Instagram pics, but that's not why they were designed, Mashable reports.
The oval shape allows the body of the plane to expand slightly at 30,000 feet instead of cracking under the pressure. Round windows, therefore, are really more a product of the invention of the pressurized cabin, which allows us to fly way high in the sky where there's less turbulence and drag.
But what would happen if the windows weren't round, exactly?
Essentially, the plane would disintegrate in mid-air as evidenced by one of the first commercial flights in 1953 that killed 43 passengers. So next time you're flying somewhere, remember to thank the clever engineers who gave your window curves.
Watch this excellent video by Real Engineering to get the full explanation of why airplane windows are round: