Principle Ballet Dancer, Ekaterina Bulgutova, of the Russian State Ballet, with the Nutcracker part of Christmas Ballet Season in Cardiff which starts at St Davids Hall on December 20, 2016 in Cardiff, England. (Photo by Kiran Ridley/Barcroft Images)

Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

“People and Space”. Winner: Wanderer in Patagonia by Yuri Zvezdny (Russia) A lone stargazer stares up at the stars of our galaxy, the Milky Way, as they stretch across the night sky over the glacier “White Stones” (Piedras Blancas) in the Los Glaciares National Park, Argentina. El Chaltén, Santa Cruz Province, Argentina, 27 September 2016 iOptron Sky-Tracker mount, Sony A7S camera, 18 mm f/2.8 lens, ISO 5000, 30-second exposure Wanderer in Patagonia. (Photo by Yuri Zvezdny/Insight Astronomy Photographer of the Year 2017)

File photo taken on July 24, 2011 shows the scenery of karst landform in Dacai Township under Maonan Autonomous County of Huaijiang, south China's Guangxi Zhuang Autonomous Region. The World Heritage Committee on Monday inscribed an extension of South China Karst, a natural World Heritage Site since 2007, into the UNESCO's World Heritage List. (Photo by Wang Xiufa/Xinhua)

Eurocopter's X³ high-speed hybrid helicopter demonstrator performs, September 6, 2010. The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Eurocopter (now Airbus Helicopters). A technology demonstration platform for Eurocopter “high-speed, long-range hybrid helicopter” or H³ concept, the X³ achieved 255 knots in level flight on 7 June 2013, setting an unofficial speed record for a helicopter. (Photo by Reuters/HO/Eurocopter/Penna)

The Oshkosh M-ATV – MRAP (Mine Resistant Ambush Protected) vehicle developed by the Oshkosh Corporation of Oshkosh, Wisconsin. It is designed to provide the same levels of protection as the larger and heavier previous MRAPs but with improved mobility and it is intended to replace M1114 HMMWVs. (wikipedia) (Photo by Alex Wong/Getty Images)

This photo taken on August 7, 2016 shows mahjong enthusiasts playing mahjong under water in a swimming pool at a diving club in the Chinese city of Chongqing. Only participants with proper diving certification were allowed to take part in the underwater competition. (Photo by AFP Photo/Stringer)

Festival-goers wash on Shipyard Island, the venue of the 24th Sziget (Island) Festival in Northern Budapest, Hungary, 15 August 2016. The venue, one of the biggest cultural events of Europe, offers art exhibitions, theatrical and circus performances and above all music concerts from 10 to 17 August. (Photo by Szabó Gábor/Origo.hu)