Elon Musk predicts a self-sustaining Mars colony within 20 years, requiring one million people and massive cargo shipments.

Elon Musk wants to send humans to Mars to establish the first Martian cities. But Mars is big. It's a planet, after all. So where should we put the first cities? The North or South poles?

His plan is to send the first humans to Mars in 2024 to build the foundations for the first Martian city. But is Mars really the best place for humans to settle? Some scientists, like Amanda ...