The Turanor PlanetSolar boat docked again in Monaco today after a 584 day trip around the world. What makes this boat ride so great is that it was the first solar-powered boat to circumnavigate the globe.
The top of the boat is covered with over four thousand square feet (500 square meters) of solar panelling. The solar panels powered both of the ship's motors, which allowed for it to go as fast as 15 mph. On days when there were no sun, the boat was equipped with lithium batteries that stored enough energy for three days so that they were never stranded at sea.
Source: Scientific American