Mars has water ice at the poles, and possibly underground too. Blocked off caves can facilitate controlled atmosphere environments.
If man can create submarines to survive for years without seeing sunlight, while submerged, and surrounded by deadly saltwater, at atmospheric pressures that can crush a human body, then man can construct a livable habitat on Mars. And we can all be assured that it will happen as soon as it is profitable enough to do so.
Mars has water ice at the poles, and possibly underground too. Blocked off caves can facilitate controlled atmosphere environments.
If man can create submarines to survive for years without seeing sunlight, while submerged, and surrounded by deadly saltwater, at atmospheric pressures that can crush a human body, then man can construct a livable habitat on Mars. And we can all be assured that it will happen as soon as it is profitable enough to do so.