Some scientists, including world-renowned physicist Stephen Hawking, believe that in order to safeguard humanity's future, we need to leave Earth and colonize another planet. But is there an alien world out there that we could call home? How would we travel across the vast distances of space to get there? And what would it take to set up a new civilization? See how visionary scientists and engineers are pushing their imaginations and ingenuity to the limits to prepare humanity for what would surely be its greatest adventure yet.