Today's Martian surface is a cold, nearly airless home. Many dream of a full renovation: warming the planet, filling it with air from carbon dioxide and nitrogen. But researchers have crunched the numbers: such a 'makeover' would require space mirrors that capture sunlight and stretch over an area the size of Africa just to melt the polar caps, plus factories pumping out gas for a thousand years. Even just making the air breathable demands energy that humanity produces over centuries. And that's only half the problem: without a magnetic field, Mars would quickly lose its new atmosphere to the solar wind.

Fortunately, instead of rebuilding the whole house, we can pitch a large tent in the best room. Domes over valleys or craters let us create an Earth-like climate in a small area. This approach is already feasible and requires far fewer resources. People could live and work inside, and even explore the planet without a full spacesuit — only needing protective gear when stepping outside.