Just over one year ago, the world’s first solar-powered plane set off on a journey around the world. Stocked with 17,000 solar cells, the so-dubbed Solar Impulse 2 looked to break a world record and highlight the feasibility of solar energy by flying the long-distance powered only by the sun.
The plane finally completed its journey, in spite of a few complications, on July 26 when it touched down in Abu Dhabi. The effort is seen by many as a pioneering example of the power or alternative energies.
This from IFLScience:
To keep its power running, the plane flew above the clouds to collect sunlight during the day, before dipping down lower at night to save its batteries. And owing to being completely solar powered, it packed a modest top speed of just 75 km/h (47 mph).