Photographers gather to take pictures of pilot Andre Borschberg (C) ahead of the take off of Solar Impulse 2-a solar powered plane- in Nanjing, China, May 31, 2015. The world's largest solar-powered airplane, Solar Impulse 2, took off from eastern China's Nanjing on Sunday to continue its round-the-world voyage. The Swiss-made plane left Nanjing's Lukou International Airport at 2:39 in the early morning, with former fighter pilot Borschberg at the controls alone for the entire 8,200-kilometer flight from Nanjing to Hawaii, the toughest leg of its marathon adventure. (Photo by Reuters/Solar Impulse)

A fuel rod is inserted into a reactor vessel inside the No. 1 reactor building at Kyushu Electric Power's Sendai nuclear power station in Satsumasendai, Kagoshima prefecture, Japan, July 8, 2015. Kyushu Electric Power Co started loading uranium fuel rods into a reactor on Tuesday, marking the first attempt to reboot Japan's nuclear industry in nearly two years after the sector was shutdown following the 2011 Fukushima disaster. (Photo by Issei Kato/Reuters)

Engine driver Josef Kowatsch (top L) steers a train through the NEAT Gotthard Base Tunnel during a media visit near the town of Erstfeld August 24, 2015. Crossing the Alps, the world's longest train tunnel should become operational at the end of 2016, consisting of two parallel single track tunnels, each of a length of 57 km (35 miles). (Photo by Arnd Wiegmann/Reuters)

This combination of August 30, 2005 and July 29, 2015 aerial photos shows downtown New Orleans and the Superdome flooded by Hurricane Katrina and the same area a decade later. Katrina's powerful winds and driving rain bore down on Louisiana on August 29, 2005. The storm caused major damage to the Gulf Coast from Texas to central Florida while powering a storm surge that breached the system of levees that were built to protect New Orleans from flooding. (Photo by David J. Phillip/Gerald Herbert/AP Photo)

Fatima Rezai, 21, a female officer from the Afghan National Army (ANA) practices with a punch bag during an exercise session at at the Kabul Military Training Centre (KMTC) in Kabul, Afghanistan October 23, 2016. (Photo by Mohammad Ismail/Reuters)

A man in a Donald Trump mask joins hundreds of other protesters and activists as they march during a demonstration near a midtown hotel which is hosting a black-tie fund-raiser for the state Republican Party on April 14, 2016 in New York City. (Photo by Spencer Platt/Getty Images)

A Vietnamese bride is seen pushing the groom on a scooter during a photo shoot for their wedding in An Bang Beach outside Hoi An in Vietnam December 11, 2016. (Photo by Reuters/Stringer)

Model Kendall Jenner poses on the red carpet as she arrives for the screening of the film “Mal de pierres” (From the Land of the Moon) in competition at the 69th Cannes Film Festival in Cannes, France, May 15, 2016. (Photo by Yves Herman/Reuters)