Partipants vie for the ball during the 11th Mud Olympics held at the North Sea coast in Brunsbuettel, Germany, July 11, 2015. Amateur athletes have competed in several disciplines at the Mud Olympics since 2004. (Photo by Axel Heimken/EPA)

An Indonesian muslim woman walks on “sea of sands” as they prepare for Eid Al-Fitr prayer at Parangkusumo beach on July 17, 2015 in Yogyakarta, Indonesia. Muslims worldwide observe the Eid Al-Fitr prayer to mark the end of Ramadan and the beginning of the new month of blessing Shawwal 1436 Hijriah. (Photo by Ulet Ifansasti/Getty Images)

A ten days old South American sea lion pup sits next to its mother Lunita at the “Tiergarten Schoenbrunn” Zoo in Vienna, Austria, July 28, 2015. The pup was born in the zoo and weighs about 14 kilograms (30 pounds). (Photo by Leonhard Foeger/Reuters)

A General Atomics MQ-9 Reaper stands on the runway during “Black Dart”, a live-fly, live fire demonstration of 55 unmanned aerial vehicles, or drones, at Naval Base Ventura County Sea Range, Point Mugu, near Oxnard, California July 31, 2015. (Photo by Patrick T. Fallon/Reuters)

In this picture taken Thursday, August 4, 2016, seal Tristan looks out of a basket while being released into the North Sea together with others at the beach of the island Juist, Germany. He is part of the first group of released seals of the seal breeding station Norddeich this year. (Photo by Carmen Jaspersen/DPA via AP Photo)

A tank rolls out from a ship on a landing operation during military drills at the Black Sea coast, Crimea, Friday, September 9, 2016. Russia has deployed cruise missiles, multiple rocket launchers, tanks and its latest anti-aircraft system at massive military drills in Crimea. The drills which began across southern Russia and Crimea earlier this week and involve over 120,000 troops are some of the largest exercises Russia has held for years. (Photo by Pavel Golovkin/AP Photo)

A man and a girl take a dip in icy waters during celebrations for the Orthodox Epiphany in the Sea of Japan in the far eastern city of Vladivostok, Russia, January 19, 2016. Orthodox believers mark Epiphany on January 19 by immersing themselves in icy waters regardless of the weather. (Photo by Yuri Maltsev/Reuters)

A polar bear cub snuggles up against her mother Valeska, in their enclosure at Bremerhaven's (Bremen's) Zoo by the Sea, Germany March 9, 2016. The female cub, who is yet to ne named, was born on December 11 last year. (Photo by Carmen Jaspersen/Reuters)