The sun-powered Solar Impulse plane is gradually working up to a trip around the globe, with the most recent benchmark being its first international flight in 2011. Now Bertrand Piccard and Andre Borschberg are taking the jumbo jet-size plane on its first transcontinental journey. The Solar Impulse set off for Morocco today, and its pilots will stop in Madrid along the way. The goal is to complete the 1,554-mile trip by next week, and the big challenge will be crossing cloudy regions like the Pyrenees mountains separating France and Spain.
