Last year, the Mars Reconnaissance Orbiter captured high-resolution images of the Red Planet which showed many mesas, valleys, and rock debris which appeared to be (geologically speaking) recent formations. A team of scientists from Brown University analyzed the photographs and found evidence that the terrain was carved by large glaciers
much more recently than they thought possible. Climate activity on Mars was thought to have quieted over 3 billion years ago, but these glaciers would have been around within the last 10-100 million years.
"The finding could have implications for the life-on-Mars argument by strengthening the case for liquid water. Ice can melt two ways: by temperature or by pressure. As currently understood, the Martian climate is dominated by sublimation, the process by which solid substances are transformed directly to vapor. But ice packs can exert such strong pressure
at the base to produce liquid water, which makes the thickness of past glaciers on its surface so intriguing."