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 walruses at Hagenbeck Zoo in Hamburg, Germany on July, 7, 2015. (Photo by Werner Struss/Startraks action)

Artist Joe Hill poses on his 3D artwork, from the “Joe and Max” project as part of an advertising campaign, during its presentation at a park in Moscow, Russia, July 4, 2015. (Photo by Sergei Karpukhin/Reuters)

An Indian student warms up during the 44th Samartha Summer Sports Coaching Camp organized by Shree Samarth Vyayam Mandir in Mumbai, India, 25 April 2018. Mallakhamba arose in the western state of Maharashtra centuries ago. It was originally practiced by wrestlers and soldiers as a strength training exercise. (Photo by Divyakant Solanki/EPA/EFE)

Factory waste including dyes from the many textile factories in the region drain into a tributary of the Citarum river on August 27, 2018 outside Bandung, Java, Indonesia. (Photo by Ed Wray/Getty Images)

Paris Photo is the largest international art fair dedicated to the photographic medium and is held each November at the historic Grand Palais in Paris, France on November 7, 2018. Since 1997, the Fair’s mission is to promote and nurture photographic creation and the galleries, publishers and artists at its source. The 22nd edition of Paris Photo will takes place Thursday, November 8 through Sunday, November 11. (Photo by IBO/SIPA Press/Rex Features/Shutterstock)

Mount Whaleback iron ore mine 23°21’32.3”S, 119°40’40.1”E. The Mount Whaleback Iron Ore Mine in the Pilbara region of Western Australia. Roughly 98% of the world’s mined iron ore is used to make steel and is thus a significant component in the construction of buildings, automobiles, and appliances such as refrigerators. (Photo by Daily Overview/DigitalGlobe, a Maxar Company)

Birds sit on the back of a zebra in the Nairobi National Park, near Nairobi, Kenya, November 21, 2018. (Photo by Baz Ratner/Reuters)