A staff member demonstrates how she puts on the helmet of a mock space suit at the C-Space Project Mars simulation base in the Gobi Desert outside Jinchang, Gansu Province, China, April 17, 2019. The facility – comprising several interconnected modules including a greenhouse and a mock decompression chamber – opened its doors to the public. (Photo by Thomas Peter/Reuters)

In this Tuesday, April 16, 2019, file photo, a visitor posing for a photo walks though azalea blossoms at Nezu Shrine during a day of mild spring weather in Tokyo. Nezu Shrine is one of the oldest shrines in Tokyo. (Photo by Eugene Hoshiko/AP Photo/File)

Leo, an orphaned Sumatran orangutan, is taken to the Sumatran Orangutan Conservation Programme rehabilitation centre. Leo will join other orangutans who have been reintroduced to the Pinus Jantho nature reserve. The SOCP has gradually formed a completely new wild population of species that have been threatened with extinction. (Photo by Sutanta Aditya/Barcroft Images)

Pittsburgh police officers stand near a Port Authority bus that had fallen into a sinkhole along 10th Street and Penn Avenue in Pittsburgh on Monday, October 28, 2019. The bus and a car fell in the sinkhole shortly before 8 a.m. One person was taken to the hospital for a minor injury. (Photo by Kristina Serafini/Pittsburgh Tribune-Review via AP Photo)

Dancers perform inside of transparent balls during the Botanical Night at Botanical Garden in Berlin, Germany, 20 July 2018. During the Botanical Night a 16 kilometre long path along the flower beds and several themed gardens are illuminated and guide to many attractions. (Photo by Hayoung Jeon/EPA/EFE)

Chilean police officers march with the puppies of future police dogs during the annual military parade at the Bernardo O'Higgins park in Santiago, Chile, September 19, 2018. (Photo by Rodrigo Garrido/Reuters)

A boy holds a machine gun at a military hardware exhibition during a swear-in ceremony for new recruits of the Russian military-patriotic club “Yunarmia” (Young army) in the Black Sea port of Sevastopol, Crimea, October 27, 2018. (Photo by Pavel Rebrov/Reuters)

A ranger watches a seal pup near the Northumberland coast, Farne Islands, UK on December 19, 2018, where the National Trust says the number of Atlantic grey seal pups has reached a record high thanks to an abundance of food and a lack of predators. (Photo by Owen Humphreys/PA Wire Press Association)