Fans are seen at the 143rd Kentucky Derby on May 6, 2017 in Louisville, Kentucky. (Photo by Michael Hickey/Getty Images)

A boat is stranded on Poyang Lake in Lushan City, China during low-water season on November 3, 2016. (Photo by Xinhua/Barcroft Images)

Julian, left, is photographed by his mother with friend Gianluca, right, under water at a public pool in Gelsenkirchen, Germany, on a hot Friday, July 3, 2015. Germany faces a heat wave with temperatures up to 38 degrees Celsius (100 degrees Fahrenheit) at the weekend. (Photo by Martin Meissner/AP Photo)

A believer dressed as a “diablo” (devil) jumps at the San Blas' (Saint Blaise) procession during the “Endiablada” festival in Almonacid del Marquesado, in central Spain February 3, 2015. In the “Endiablada”, an undated traditional festival in honour of the Candelaria Virgin and San Blas, believers are dressed in colourful costumes, wear a mitre with lead cowbells tied to their waists that ring as they wander around the village and in front of the saints' statues during their processions. (Photo by Susana Vera/Reuters)

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)

“Warming up”. This photo I capture in the early afternoon, the animal species of lemurs fly. Photo location: Sambas, West Kalimantan, Indonesia. (Photo and caption by Hendy Mp/National Geographic Photo Contest)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

Model Joanna Krupa poses during a protest against animals in circuses, in front of the Houses of Parliament in London, Britain, September 11, 2017. (Photo by Hannah McKay/Reuters)