Elon Musk has founded or co-founded several ambitious companies focused on renewable energy, space exploration, and transportation. These include Tesla (electric vehicles), SpaceX (private spaceflight), Neuralink (brain-computer interfaces), The Boring Company (tunnel construction), SolarCity/Tesla Energy (solar energy), Hyperloop (high-speed ground transport), OpenAI (artificial intelligence research), and he hopes to bring self-driving cars to market through Tesla before 2020. With each new company, Musk's goal is to advance technology and make products like green energy, space travel, and transportation more affordable and accessible.