Hundreds of hardy swimmers across Britain braved jumping into freezing cold waters for a annual Christmas Day dip on December 25, 2017. (Photo by Dave Nelson/The Sun)

A group of people perform yoga on the bank of the river amidst heavy fog on a cold winter morning in Narayanganj, Bangladesh on December 9, 2020. (Photo by Mushfiqul Alam/NurPhoto via Getty Images)

Participants cross cold and muddy waters during the Strong Race competition near Tukums May 4, 2014. About 6500 people competed in this extreme running race, which includes cross-country running, elements of agility and power discipline. (Photo by Ints Kalnins/Reuters)

India's Central Reserve Police Force personnel take part in a rehearsal for the Republic Day parade on a cold winter morning in New Delhi January 8, 2014. (Photo by Ahmad Masood/Reuters)

These horses are pictured in the Khentii province in eastern Mongolia during the Winter Horse Festival – where skillful horsemen gather to challenge the strength of their horses and show off their riding skills. Pictures were taken by Batzaya Choijiljav, a travel company director from Mongolia. Here: The fur of a horse ices up in the –40 cold of Mongolia. (Photo by Batzaya Choijiljav/Caters News)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

A women drink outside the disco bar on September 18, 2020 in Wuhan, Hubei province, China. As there have been no recorded cases of community transmission in Wuhan since May, life for residents is returning to normal. (Photo by Getty Images)

People rollerblade along the beach a day before renewed restrictions due to a surge of coronavirus disease (COVID-19) cases in Los Angeles, California, U.S. November 29, 2020. (Photo by Brandon Bell/Reuters)