If you were around in the '80s, you might recall the widespread fear over the discovery of a massive hole in the ozone layer over Antarctica.
It's still there, but NASA says 2017 delivered a daintier hole than usual.
The ozone layer acts as a protective shroud over the Earth, blocking out ultraviolet radiation.
NASA likens it to an atmospheric version of sunscreen.
Our planet wouldn't be habitable without the ozone layer to help protect us from the sun.
NASA and the US National Oceanic and Atmospheric Administration have been monitoring the ozone hole since it was first discovered in 1985.