South Korea's Amry Special Warfare Command (SWC) soldiers aim their machine guns in a frozen river during a winter exercise in Pyeongchang, South Korea, Thursday, January 8, 2015. About 200 SWC soldiers participated in this routine two-week winter drill. (Photo by Ahn Young-joon/AP Photo)

A woman sits behind a bicycle on a cold winter morning in New Delhi, December 31, 2019. (Photo by Anushree Fadnavis/Reuters)

A participant competes in the “Farinato Race” winter extreme run competition in Gijon, northern Spain, January 31, 2016. (Photo by Eloy Alonso/Reuters)

Snow covered pine tree reaches for the sky. Shot in Sweden on a crisp winter day. (Photo by Anna Rebecka Lindberg/The Guardian)

A goat wearing a jacket is seen on a farm on a cold winter morning in New Delhi, India on January 3, 2023. (Photo by Anushree Fadnavis/Reuters)

Goats covered with cloth are tied next to a hut on a cold winter morning in New Delhi on December 26, 2023. (Photo by Arun Sankar/AFP Photo)

National Geographic photographer Steve Winter has spent most of his adult life shooting wild cats. Photo: A 14-month-old cub, cooling off in a pond, is riveted by a deer that appeared near the shore. Tigers are powerful swimmers; they can easily cross rivers four to five miles wide and have been known to swim distances of up to 18 miles. (Photo by Steve Winter/National Geographic)

A member of the public wears a pandemic face mask ahead of the prime minister announcing the government's Covid-19 winter strategy on September 13, 2021 in Manchester, England. Tomorrow, British Prime Minister Boris Johnson will set out his plan to manage Covid-19 through the winter, including what actions would need to be taken if the NHS hospital system were at risk of being overwhelmed. (Photo by Christopher Furlong/Getty Images)