The mysterious object was spotted several years ago by a NASA probe, and to this day nobody is quite sure what it is or how it got there
"When people find out about that they are going to say, 'Who put that there? Who put that there?'"
These are the words of Buzz Aldrin, the second man to walk on the Moon, in 2009. He was talking about a peculiar and solitary large rock, a monolith, that sits on the surface of the Martian moon Phobos.