Imagine a tightly packed city where one power grid failure cascades into chaos. Now scale that to Earth: interconnected, urbanized, vulnerable to pandemics, climate shocks, asteroids. I think solving Earth's problems matters, but none of it matters if civilization gets wiped out in one event. Mars colonization is the backup drive for humanity. It forces breakthroughs in closed-loop life support, clean energy, and automation that eventually help cities too. Prioritizing Mars isn't abandoning Earth; it's buying species-level insurance first.