Pierre Casiraghi (R), the younger son of Caroline, Princess of Hanover, and his partner Beatrice Borromeo, sit in the control centre for the Solar Impulse 2 solar powered aircraft in Monaco early on March 9, 2015, during the planes take-off from Abu Dhabi in the first attempt to fly around the world in a plane using solar energy. The flight of Solar Impulse 2 will cap 13 years of research and testing by two Swiss pilots with a round-the-world trip in which it will land 12 times and last about 25 days spread over five months.   AFP PHOTO / VALERY HACHE        (Photo credit should read VALERY HACHE/AFP/Getty Images)