It's a natural geologic feature: NASA after pic of 'door' on Mars goes viral

After a pic appearing to show a "door" on Mars went viral, NASA's Curiosity Rover tweeted "Some of you have noticed this image I took...Sure, it may look like a tiny door, but really, it's a natural geologic feature!" "It may just look like a door because your mind is trying to make sense of the unknown," it wrote.