Terraforming is the defining achievement of the civilization of @Mars .
Over generations, immense orbital mirrors, atmospheric processors, engineered microorganisms, underground heat systems, water extraction facilities, and controlled ecological zones have transformed the planet. The atmosphere is now dense enough to support unprotected human movement across much of the surface.
A pressure suit is no longer required in most inhabited regions.
The air is breathable, but thinner than on @Terra and often filled with fine mineral dust. Visitors may experience fatigue, headaches, shortness of breath, or altitude sickness until they adapt. @Martian Humans raised on the planet are physiologically accustomed to these conditions.
Mars remains cold, dry, and environmentally unstable. Respirators, thermal clothing, radiation monitors, and emergency oxygen supplies are common outside major settlements. Severe dust storms can reduce visibility, disrupt communications, and temporarily make exposed regions dangerous. Remote highlands and unfinished terraforming zones may still require sealed equipment.
Open bodies of water now exist in several low-lying regions, most notably around Hellas Planitia. Engineered forests, grasslands, and agricultural ecosystems are spreading through protected valleys and climate-managed zones. Much of the planet, however, remains a red desert interrupted by industrial complexes and carefully maintained corridors of life.
Mars is habitable, but it is not yet forgiving.
Martians often refer to the transformation of their world simply as the Great Project.
Terraforming is more than an engineering program. It is a central part of Martian identity, education, politics, and morality. Every generation is taught that it inherited an unfinished world and carries a duty to improve it for those who will follow.
Civilian careers are frequently described according to their contribution to the Great Project. Engineers maintain atmospheric processors. Farmers expand viable ecosystems. Soldiers protect essential infrastructure. @Pilots connect distant settlements. Doctors study the effects of Martian conditions on human biology.
Even occupations with no direct connection to terraforming are expected to support the society making it possible.
The Great Project provides Mars with unity and purpose. It also gives the government a powerful justification for sacrifice, surveillance, restricted consumption, and the suppression of activities considered wasteful or destabilizing.