In March 2015 Solar Impulse 2 took off from Abu Dhabi and tonight it has successfully returned, completing a 40,000km+ round the world trip. It managed the feat "without using a drop of fuel," becoming the first to manage the feat thanks to sunlight, piloted by Bertrand Piccard and Andre Borschberg. Its arrival is a bit delayed, partially due to some problems with heat-related battery damage, but just making the trip helps the project's goal to show off the potential of transportation powered by green energy sources.