If we are to go to Mars, we'll need to find water near the equator, and planetary geologists have found it, says the Physics arXiv Blog: "At the poles, the ice is there all year round. And there is good evidence that it can be found just below the surface of latitudes down to 45 degrees. But the polar regions are cold, ever-changing and hazardous. If humans ever visit Mars, they'll have to first land near the equator, where the red planet is milder and more hospitable. That may just have become more feasible thanks to...evidence of water ice...at tropical latitudes as low as 25 degrees."