Two Herens cows lock horns during the qualification round of the annual “Battle of the Queens” cow fight finals in Aproz, in the western Alpine canton of Valais May 5, 2013. Each year when taken to the alpine pastures, the cows test their strength and fight for the herd's leadership. The competition continues until a new queen has forced all the other cows to retreat. (Photo by Valentin Flauraud/Reuters)

A seafood vendor moves a giant swordfish to his stall at a market in Qingdao, Shandong province, China, September 12, 2015. The 4.1-metre-long (13.5 feet) swordfish, weighed about 309.5 kilograms (682 lbs), was caught by local fishermen on Friday, local media reported. (Photo by Reuters/Stringer)

A witch doctor prepares an offering for the inauguration of the World People's Conference on Climate Change and the Defense of Life, prior to the World Climate Change Conference, in Tiquipaya, Bolivia, October 10, 2015. Almost 150 nations, including major emitters led by China and the United States, have submitted plans to the United Nations for curbing greenhouse gas emissions blamed by the U.N. for causing more floods, droughts and heat waves. France will host the conference in Le Bourget, near Paris, from November 30 to December 11, 2015. (Photo by David Mercado/Reuters)

A demonstrator dressed as Santa Claus holds up a flag as a riot police vehicle releases a jet of water during a protest against the private system of pension fund administrators in Santiago, Chile, December 10, 2015. The flag reads “Classist Workers Union”. (Photo by Ivan Alvarado/Reuters)

Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

Urszula Sidoruk, 19, from the paramilitary group SJS Strzelec (Shooters Association), trains her workout at a gym in Siedlce, eastern Poland March 18, 2014. Inspired by the war in Ukraine, growing numbers of Poles are joining volunteer paramilitary groups, where they receive basic army training and prepare to defend their homeland. (Photo by Kacper Pempel/Reuters)

Participants pass an egg using their mouths during a religious ritual as they play the role of traditional fighters in a parade during the Popo (Mask) Carnival of Bonoua, in the east of Abidjan, April 18, 2015. The carnival has its origins in the changes that Aboure youths in Bonoua introduced to the annual festival of yams. (Photo by Luc Gnago/Reuters)

Lightning illuminates a thundercloud as a storm front hits the North Sea region near Westerhever, northern Germany, on August 11, 2014. (Photo by Daniel Reinhardt/AFP Photo/DPA)