A man smashes an apple with a sword placed on the head of a man wearing a knave costume during the Easter knight event on April 21, 2014 in Berlin. The easter knight event delivers an insight into medieval lifestyle. (Photo by Rainer Jensen/AFP Photo/DPA)

A brown bear is checked by foreign veterinaries and local staff members at the Four Paws Bear Sanctuary in Pristina, on May 9, 2014. (Photo by Hazir Reka/Reuters)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

Miniature spring-wound 35-mm film camera in a modified cigarette pack. The Tessina’s small size and quiet operation provided more options for concealment than most commercially available models. (Photo by Central Intelligence Agency)

Yerevan residents celebrate Armenian Prime Minister's Serzh Sargsyan's resignation in Yerevan, Armenia, Monday, April 23, 2018. Sargsyan resigned unexpectedly on Monday, an apparent move to bring to an end massive anti-government protests. (Photo by Amos Chapple/RFE/RL)

The moon is seen in its waxing gibbous stage as it rises behind the helicopter from the original Batman television show, which people can ride at the New Jersey State Fair, Saturday, June 22, 2013, in East Rutherford, N.J. The moon, which will reach its full stage on Sunday, is expected to be 13.5 percent closer to earth during a phenomenon known as supermoon. (Photo by Julio Cortez/AP Photo)

Female pilot Anna climbs out the cockpit of Japanese electronics company Suidobashi Heavy Industry's newly unveiled robot “Kuratas” at the Wonder Festival in Chiba, suburban Tokyo on July 29, 2012. The “Kuratas” robot, which will go on sale with a price tag of one million USD, measures four meters in height, weighs four tons and has four wheeled legs that can either be controlled remotely through the 3G network or by a human seated within the cockpit. (Photo by Yoshikazu Tsuno/AFP Photo)

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)