Mars

Mars is the fourth planet in the Sol System, and one of the first robotic exploration destinations of the Humans of Earth. As humanity reached beyond their terrestrial cradle, Mars was the first to be terraformed.

Era I
During humanity's growth from their home, Mars became the subject of colonizarion efforts, and was the first planet to be terraformed. CO2 was extracted from Venus's atmosphere and transported to Mars to build up the atmosphere.