Swiss pilot Bertrand Piccard prepares for a test flight of the solar-powered Solar Impulse 2 experimental aircraft in Payerne November 13, 2014. The aircraft, weighing 2.4 tons with a wingspan of 72 meters, is fitted with more than 17,000 solar cells. An attempt to fly around the world in stages using only solar energy will be made in 2015. (Photo by Ruben Sprich/Reuters)

A handout picture provided by Solar Impulse on 18 March 2015 shows the Swiss solar-powered plane Solar Impulse 2, HB-SIB, taking off with Swiss explorer Andre Borshberg on board for the third leg Ahmedabad to Varanasi, of the Round-The-World, in Ahmedabad, India, 18 March 2015. Swiss explorers Bertrand Piccard and Andre Borschberg attempt to circumnavigate the world flying with an aircraft, with a 72 metres wingspan, powered only by solar energy without a drop of fuel. (Photo by EPA/Solar Impulse)

A destroyed T-72 tank, which presumably came from Russia, is seen on a battlefield near separatist-controlled Starobesheve, eastern Ukraine, October 2, 2014. The burnt-out remains of dozens of tanks and armoured vehicles in fields near the small village of Horbatenko bear witness to the ferocity of a battle that turned the tide of the conflict in eastern Ukraine. Among the debris, Reuters found the blackened carcasses of what military experts have since identified as two Russian army tanks, supporting statements by Kiev and the West that the rebels were backed by troops and equipment sent by Moscow. (Photo by Maria Tsvetkova/Reuters)

Stunning images taken by Sean Lenz, 19, and Kristoffer Abligaard, 20, show picturesque waterfalls transformed into vibrant rainbows of colour. The awe-inspiring images were created by clever use of long exposure photography and glow sticks floating through water. Photo: Picturesque waterfalls transformed into rainbows of colour. (Photo by Sean Lenz/Kristoffer Abildgaard)

A South Korean woman looks out at the flood water after a torrential rain storm hit the capital city on July 27, 2011 in Seoul, South Korea. South Korea issued a national crisis warning on as torrential rain caused flooding in parts of the country, killing over 35 with at least ten missing. (Photo by Chung Sung-Jun/Getty Images)

A Geoffroy's Monk Saki is seen at the Parque de Las Leyendas zoo in Lima, Peru, February 14, 2018. (Photo by Guadalupe Pardo/Reuters)

Emily Ratajkowski and Vanessa Hudgens attend the 73rd Annual Tony Awards at Radio City Music Hall on June 09, 2019 in New York City. (Photo by Mike Coppola/Getty Images for Tony Awards Productions)