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)

This computer image provided Monday March 17, 2014 by the Press Office of socialist candidate to Paris Mayor Anne Hidalgo, shows a tunnel of abandoned railway from the 19th century, now ramshackle and overgrown, turned into a cinema. Hidalgo’s plan envisions not just a green space but in the tunnels, places for farming fish and mushrooms. (Photo by AP Photo/Anne Hidalgo's Press Office)

A close up of a caracal lynx's face looking into a camera on January 2014 in Western Cape, South Africa. (Photo by Dale Morris/Barcroft Media)

In this September 1, 2014 photo released by the U.S. Geological Survey, fluid lava streams from the June 27 lava flow from the Kilauea volcano in Pahoa, Hawaii. The June 27 lava flow is named for the date it began erupting from a new vent. The Hawaiian Volcano Observatory issued a warning Thursday, September 4, 2014 to a rural community in the path of a lava flow on Hawaii's Big Island, as the molten rock moved to within a mile of homes. Observatory scientists said lava from the Kilauea volcano could reach the Kaohe Homesteads in five to seven days if it continues advancing through cracks in the earth. (Photo by AP Photo/U.S. Geological Survey)

A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

A group of hikers atop Mount St. Helens on July 21, 2016. Mount St. Helens or Louwala-Clough is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 96 miles south of Seattle, Washington, and 50 miles northeast of Portland, Oregon. (Photo by Raxit Kagalwala)

A boy covers his head with fallen leaves as he enjoys a stroll with his family in a park in downtown Frankfurt, Germany, November 6, 2016. (Photo by Kai Pfaffenbach/Reuters)

Meropidae are seen on a rock in Van in Turkey on March 03, 2018. (Photo by Ali Ihsan Ozturk/Anadolu Agency/Getty Images)