Mars has long been a source of inspiration, imagination and, lately, aspiration for many. It has generated a breadth of beliefs and ideas, as well as hope for a bright future there. However, the red planet will never offer a fresh start: we would carry with us some of our culture and our politics. Our future there would remain connected to Earth’s history, particularly human history. In the present chapter, humanity’s relationship to Mars is discussed from a broadly historical, cultural, and ethical perspective, in order to provide a backdrop for the later inquiry of a variety of issues—ethical, societal, and political—related to Mars exploration and settlement. Political drivers for establishing a Mars settlement are then discussed. The chapter ends on a more practical note: on planetary protection, and the threat posed thereto by human-borne microbes. One way or another, terrestrial beings will alter the Martian environment. The ethical concerns this raises cannot be left unaddressed.