McMurdo Dry Valleys, Antarctica
Credit: Hubertus Kanus / Getty Images

NASA chose this windswept Antarctic expanse as a stand-in for Martian plains due to its low humidity and frigid temperatures. Unlike most of the continent, the ground in the dry valleys is laid bare thanks to steep mountains that block encroaching sea ice and powerful gusts of wind that can reach hurricane speeds, evaporating any moisture in the area. Unsurprisingly, there's very little life in the area, save for scattered patches of moss and tiny invertebrates. There is some water, but it's not exactly drinking material. Don Juan Pond is the saltiest body of water on the planet, allowing it to remain liquid even when the water reaches subzero temperatures.