Elon Musk, the Twitter deal and his quest to save ‘all life on Earth’

On the tech entrepreneur's missions for Mars and social media. Elon Musk has positioned himself as a meme celebrity and a star inventor. So how did he cultivate a personality that is both an open book and an elusive enigma? Marc Fisher, Christian Davenport and Faiz Siddiqui explore how his Twitter deal fits with his lifelong quest to spark innovation, make money and save humanity.