People have been enthralled by the red planet, Mars, for centuries, long before the blockbuster book and movie The Martian. The planet has been known since antiquity, but if NASA gets its way, human beings may set foot there as early as 2030. (Getting off the place is actually the trickiest part.)

What we know about Mars keeps evolving, thanks to remote sensing and unmanned missions like NASA's Curiosity rover. There's a lot we don't know, including whether the red planet ever harbored life, how its atmosphere got the way it is, and what happened to the oceans that apparently used to cover much of its surface. 

From the above video, here are a few fast facts about Mars, based on