The Dry Valleys, Antarctica
The Dry Valleys is one of the most extreme places in the world. It is so bone-dry, and experiences such little precipitation, that snow doesn't even collect here. The air is also bone-cold, and the wind chill is merciless; katabatic winds can race through these valleys at 200 mph. Despite these harsh conditions, though, space scientists still flock here because the Dry Valleys might represent the closest analogue we have on Earth to the dry, cold, windswept plains of Mars.
And even more promising: Somehow, even in this barren place, life exists. It may seem counterintuitive, but the Dry Valleys also contain Antarctica's longest river, the Onyx. This trickle of a river offers a glimpse of how flowing water, no matter how scarce, can become a habitat for rugged organisms in the harshest of places. There are no fish in the Onyx, but there are microorganisms and algal blooms. Scientists hope that by studying these life-forms, they might get a glimpse of how life survives on other planets.