The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

A pro-Russian supporter with the Russian national flag on her shoulders takes part in a meeting in Simferopol, March 6, 2014. Crimea's parliament voted to join Russia on Thursday and its Moscow-backed government set a referendum within 10 days on the decision in a dramatic escalation of the crisis over the Ukrainian Black Sea peninsula. (Photo by Vasily Fedosenko/Reuters)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/AP Photo)

A girl picks catkins at a field amid the COVID-19 pandemic in Sarighat, on the outskirts of Dhaka, Bangladesh, October 2, 2020. (Photo by Mohammad Ponir Hossain/Reuters)

A man wearing the traditional Carnival Neapolitan mask of Pulcinella performs on Via Caracciolo avenue in Naples, Italy, Saturday, November 14, 2020. The regions of Campania and Tuscany were designated red zone on Friday, signaling the dire condition of a hospitals struggling with a surge of new admissions. (Photo by Gregorio Borgia/AP Photo)

Supporters of US President Donald Trump rally in front of a poll station at Coral Gable Branch Public Library in Miami, Florida on November 3, 2020. (Photo by Eva Marie Uzcategui/AFP Photo)

A woman wearing a face mask takes a photo on her phone in Covent Garden, London, Thursday, December 3, 2020. Britain became the first country in the world to authorize a rigorously tested COVID-19 vaccine Wednesday and could be dispensing shots within days – a historic step toward eventually ending the outbreak that has killed more than 1.4 million people around the globe. (Photo by Alberto Pezzali/AP Photo)