Performers are seen as a 90-year old spruce tree cut down in the woods of the Shchyolkovsky District in Moscow Region, Russia on December 16, 2021 is sent to Moscow. The almost 28-metre high tree will be put up at the Moscow Kremlin's Sobornaya (Cathedral) Square this New Year and Christmas. (Photo by Vasily Fedosenko/TASS)

A government awareness poster for wearing surgical masks is seen reflected and upside-down in the Dambovita river in Bucharest, Romania, 19 November 2020. The poster, depicting a man wearing a surgical mask, reads: “I WEAR A MASK BECAUSE I KNOW THAT ONLY TOGETHER WE WILL SUCCEED!”. As the number of COVID-19 infections increased, authorities decided that wearing a protective mask should become mandatory at all times in all public places. (Photo by Robert Ghement/EPA/EFE)

Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

An Afghan vendor selling birds to be kept as pets wait for customers in his shop in Kabul on December 11, 2021. (Photo by Ahmad Sahel Arman/AFP Photo)

People walk along the Neva River at sunset in St.Petersburg, Russia, Tuesday, December 6, 2016. The temperature in St.Petersburg is –9C ( 15.8 °F). (Photo by Dmitri Lovetsky/AP Photo)

A model walks the runway during the Neo Fashion show during Berlin Fashion Week Autumn/Winter 2020 at Vienna House Adel's on January 13, 2020 in Berlin, Germany. (Photo by Robert Schlesinger/Getty Images for Neo.Fashion.2020)

Australia's State Emergency Service (SES) personnel gather at the scene of a light plane crash near the Capital Golf Course, in Melbourne, Australia, 22 June 2021. A pilot was injured and rushed to hospital after his light plane crashed shortly after taking off from Moorabbin Airport. (Photo by James Ross/EPA/EFE)