A long time ago, Mars wasn't the barren lump of rock and dust that it is today. Evidence gathered by rovers and satellites such as Curiosity and the Mars Reconnaissance Orbitersuggests that, billions of years ago, the Red Planet was once covered in lakes and oceans, and that it had a thicker atmosphere. It may have even supported life. Any water and life is now gone, but once upon a time, Mars might've looked a lot like Earth