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)

A member of the 324 Squadron during the Anzac Day dawn service at Coogee Beach in Sydney, Australia on 23 April 2019. Anzac Day, held annually on 25 April, is a national day of remembrance across Australia and New Zealand, which commemorates the people who lost their lives or served in wars and conflicts. The day coincides with the first landing of the Anzacs at Gallipoli, Turkey, in World War One. (Photo by Steven Saphore/Australian Associated Press)

An Indigenous man stands under a water fountain outside a government building in Brasilia, on April 26, 2019, during the last day of a protest camp. Approximately 4,000 indigenous people from different tribes are taking part in protests during the Indigenous National Mobilization (MNI) week, a mobilization which seeks to tackle territorial rights' negotiations with the government. (Photo by Carl De Souza/AFP Photo)

An elephant “kisses” a visitor during a show at an elephant training school in Xishuangbanna, Yunnan province, April 18, 2015. Some 16 elephants live at the school and give four 30-minute performances everyday for visitors. (Photo by Wong Campion/Reuters)

In this April 2, 2015 photo, dog owner Laura Aquilina strolls with her two year old Rottweiler Brutus, who was recently fitted with prosthetics on all four paws, and is currently learning to use them, near Aquilina's home in Loveland, Colo. Brutus lost all four paws to frostbite as a puppy while under care of a breeder, and Aquilina began caring for him about a year ago. (Photo by Brennan Linsley/AP Photo)

An Israeli boy swims next to sheep belonging to a Palestinian farmer in the West Bank village of Al-Auja in the Jordan Valley on April 8, 2015 during the Jewish Passover holiday. Thousands of Israelis spent the day outdoors, picnicking and touring the country during the eight-day Passover holiday, which commemorates the Israelites' exodus from Egypt some 3,500 years ago. (Photo by Menahem Kahana/AFP Photo)

This artist image released from Japan's airline All Nippon Airways (ANA) on April 17, 2015 shows ANA's Boeing 787-9 aircraft into the colors of R2-D2 robot of Star Wars. Japanese air carrier ANA will place the special colored jetliner in service in this autumn. (Photo by AFP Photo/All Nippon Airways)

Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)