Mars

Being second smallest planet in the system, Mars carries the name of the Roman god of war. Iron oxide on its surface gives it its unmistakable look visible to the naked eye. Home to the system's highest known mountain, Olympus, Mars is a desolate desert. Once half-covered in liquid water, Mars lost its magnetic field due to presumably stopped rotation of its iron core, and its atmosphere was soon to follow - evaporated by the unforgiving solar winds. Mars is solely populated by robots.