Startling new images of Mars show a large circular sign and giant, claw-like scratches — What the heck is that? The Mars Express probe has been working in Mars orbit since 2003. It has just sent back extraordinary images of one region of the Red Planet.

https://medium.com/@darkmatterarticles/startling-new-images-of-mars-show-a-large-circular-sign-and-giant-claw-like-scratches-what-the-4432d56b6bab