Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

A member of the “Sibspas” Siberian search and rescue group dressed as Santa Claus (R), waits for his team mate, dressed as Father Frost, the Russian equivalent of Santa Claus, as he climbs the rock named “The Fourth Stolb” (the Fourth Pillar) at the Stolby national nature reserve during a training session of the Russian Emergencies Ministry, outside the Siberian city of Krasnoyarsk, Russia December 15, 2015. (Photo by Ilya Naymushin/Reuters)

South Korean workers are seen from a crane as they work on the 123rd floor during the framing completion ceremony of the 'Lotte World Tower' in Seoul, South Kora, 22 December 2015. The building's exterior was completed in a final height of 550 meters, and 123 floors. The ceremony came five years and two months after the construction of the building began and its opening will likely take place at the end of next year when the interior work is set to be completed, the South Korean Yonhap news agency reported. The building is the highest in South Korea and the fifth highest in the world, according to Yonhap. (Photo by Jeon Heon-Kyun/EPA)

A boy and a woman run across a railway track as a train approaches in Chengdu, Sichuan province, China, October 8, 2015. Many residents disregard sign prohibiting this kind of illegal crossing and choose to do so to save time, local media reported. (Photo by Hao Fei/Reuters/Western China Metropolis Daily)

Men slide in the mud during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Saturday, July 22, 2017. The 20th annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

The ruins of a castle stand above the town of Rocca Calascio, close to Santo Stefano di Sessanio in the province of L'Aquila in Abruzzo, inside the national park of the Gran Sasso e Monti della Laga, Italy, September 7, 2016. (Photo by Siegfried Modola/Reuters)

This picture taken on October 20, 2016 shows students practising wushu at the Tagou martial arts school in Dengfeng. China is investing hugely in football training and has vowed to have 50 million school- age players by 2020, as the ruling Communist party eyes “football superpower” status by 2050. (Photo by Nicolas Asfouri/AFP Photo)

A woman tour skates on the frozen lake of Orlangen, south of Stockholm, Sweden, on December 23, 2016. Tour skating is recreational long distance ice skating on natural ice particularly popular in the Nordic countries. (Photo by Tobias Roestlund/AFP Photo/TT News Agency)