Visitors look at tropical fish transported from Japan's southern island of Okinawa displayed in a giant 14-ton fish tank at the Sony Square event space in Tokyo on July 17, 2016. The 45-day-long summer exhibition will be held through August 28 to display sea creatures common to the waters around Okinawa. (Photo by Kazuhiro Nogi/AFP Photo)

North Korean leader Kim Jong Un, his wife Ri Sol Ju and Song Tao, head of the International Department of Communist Party of China (CPC) Central Committee, applaud with ballet dancers in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang April 17, 2018. (Photo by Reuters/KCNA)

A visitor is reflected in a light installation at Mulberry Lights on Regent Street in London, UK on November 16, 2018. Visitors have fun taking selfies and posing with the colourful light installations. Mulberry Lights is a series of illuminating interactive experiences that celebrate how light, colour, shapes and people come together to create a modern British Christmas. (Photo by Imageplotter/Rex Features/Shutterstock)

Olaf Niess catches swans on the river Alster near the town hall in Hamburg, Germany, 17 November 2015. The Alster swans are moving to their ice-free winter quarters on the Eppendorf Muehlenteich millpond until spring. (Photo by Bodo Marks/EPA)

An Iraqi Muslim woman walks past Christmas decorations for sale in the Shiite holy city of Najaf on December 17, 2015. (Photo by Haidar Hamdani/AFP Photo)

Britain Horse Racing, Royal Ascot, Ascot Racecourse on June 17, 2016. Chelsea pensioners with a racegoer posing between them. (Photo by Toby Melville/Reuters/Livepic)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

A spectator shows off her green, white and gold eyelashes as the annual Saint Patrick's day parade takes place on March 17, 2018 in Dublin, Ireland. Dublin hosts the largest Saint Patrick's day parade in the world with a route spanning 2.5 km. The Irish annals for the fifth century date Patrick's arrival in Ireland in the year 432 with the patron saint of Ireland's remains believed to be buried at Down Cathedral in County Down. (Photo by Charles McQuillan/Getty Images)