SpaceX to build self-growing city on Moon in less than 10 years: Elon Musk

SpaceX CEO Elon Musk said the space venture can potentially build "a self-growing city on the Moon" in under 10 years. He added that SpaceX will also build a Mars city, but that'd take over 20 years. "It's only possible to travel to Mars when the planets align every 26 months...whereas we can launch to...Moon every 10 days," he said.