It started as a crazy dream: Could a jetliner really fly using nothing more than solar energy? National Geographic goes inside the nearly 10-year journey of the engineers who created Solar Impulse HB-SIA, from the first brainstorming session until it took flight. Witness the success of the 26-hour flight a nonstop day-night-day sequence of the Solar Impulse plane that turned a crazy dream into a clean energy icon.
