Beach  Rocks and MossDesign 133Leaf Rain Green Nature ForestKristen StewartCute   202People   326Ios9 Apple Wave Rainbow Sea Ocean RedMusic   102Dessert Curves Mountain NatureGreen Dark Field Nature Mountain BwPink Ioi Chaeyeon Cute Kpop AsianBuilding Window Blue PatternButterfly Eating Time NatureWood Nature Cut Pattern White BwPeople   169Nana Kpop Model White Beauty Celebrity FlareApple Color Logo Illustration ArtSuji Romantic Purple Kpop GirlBeach   16Batman VS Superman Movie FightThis artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres.