You probably know that Mars hasn't always been so barren, but have you wondered what it was like in its heyday? You almost wouldn't recognize it, according to an international team of scientists. They've used six years of atmospheric monitoring to determine that Mars had enough water to form a big but shallow (one mile deep) ocean that covered almost half of the northern hemisphere four billion years ago. The artist's rendition above gives you an idea of what it might have looked like -- the Red Planet would have been decidedly blue in places. Read more http://www.engadget.com/2015/03/08/mars-once-had-large-ocean/