A team of researchers have identified a 12-mile wide salty lake underneath a massive glacier on Mars using a ground-penetrating radar aboard the European Space Agency's (ESA) Mars Express orbiter. This discovery opens up the possibility that microbial life may exist on Mars, as well as the potential for human water supplies. While scientists have spotted water on Mars before, these previous discoveries were centered mostly around ephemeral surface water that likely appear and disappear over short time periods. This new discovery opens the door for the possibilities of underworld life on Mars, especially since the conditions on the surface are so hostile. Although it is likely that this supposed lake is extremely cold and salty, this discovery is definitely a ground-breaking one (no pun intended).