On the surface, the red planet’s freeze-dried world of rocks, ice, and dust looks like an unlikely place to plant a garden. But rocks and minerals found by the Mars rovers show it must once have had warmer, habitable living conditions. Now, using photorealistic CGI visualizations, we’ll make a science fiction dream of Mars — a world of trees, rivers, and blue skies — a plausible future, bringing it to life after three-and-a-half billion years in a deep freeze.