Soldiers of China's People's Liberation Army (PLA) jump as part of their winter training in temperature of negative 26 degrees Celsius at China's border with Russia in Heihe, Heilongjiang province, December 14, 2015. (Photo by Reuters/Stringer)

Tourists watch the Christmas Day sunrise behind Diamond Head from Waikiki Beach in Honolulu, Friday, December 25, 2015. (Photo by J. David Ake/AP Photo)

A salsa dancer performs in the “Salsodromo” parade, which marks the start of the Fair of Cali, Colombia, December 25, 2015. Picture taken December 25, 2015. (Photo by Jaime Saldarriaga/Reuters)

Paramilitary policemen take part in a training in Chaohu, Anhui province, China December 28, 2015. (Photo by Reuters/China Daily)

Performers of Everland Amusement Park present the part of Christmas Fantasy in downtown of Myundong in Seoul, South Korea on December 3, 2019. (Photo by Seokyong Lee/Penta Press/Rex Features/Shutterstock)

Pedestrians wear masks as smoke and haze from bushfires in New South Wales blankets the CBD in Sydney, Australia, 10 December 2019. The New South Wales environment department says visibility across east and southwest Sydney was at a “hazardous” level on Tuesday morning, while air quality was poor in southwest Sydney and hazardous in northwest Sydney. (Photo by Steven Saphore/EPA/EFE)

This handout picture taken and released by Thai Royal Household Bureau on December 12, 2019 shows Thailand's Princess Bajrakitiyabha (L) and Princess Sirivannavari sit in their barge during the Royal Barge procession in Bangkok. The Royal barge procession is the final event of the coronation of Thailand’s King Maha Vajiralongkorn. (Photo by Thai Royal Household Bureau via AFP Photo/Handout)

Female activists perform a choreography originated in Chile, and inspired by the Chilean feminist group Las Tesis, to protest against gender violence and patriarchy in front of the Greek parliament at Athens' Syntagma Square on December 22, 2019. (Photo by Louisa Gouliamaki/AFP Photo)