Pilot Bertrand Piccard tests equipments before departure at Nanjing Lukou International Airport in Nanjing, capital of east China's Jiangsu Province, May 31, 2015. The Swiss-made solar-powered plane Solar Impulse 2 left China for Hawaii on Sunday. It will fly across the United States and make several stops before finally reaching Abu Dhabi. (Photo: Xinhua/Sun Can)
