A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

Swiss police officers stand beside of mock gates of the NEAT Gotthard Base Tunnel inside the event hall for the upcoming opening ceremony near the town of Erstfeld, Switzerland May 31, 2016. The celebrations of the opening of the Gotthard Base Tunnel will start on June 1, 2016. With a length of 57 km (35 miles) crossing the Alps, the Gotthard Base tunnel is the world's longest train tunnel. (Photo by Arnd Wiegmann/Reuters)

A crocodile at a zoo in the southern Taiwan city of Kaohsiung holds the forearm of a zoo veterinarian in its teeth, April 2007. Surgeons in Taiwan have reattached a vet's arm, after it was bitten off by a crocodile as he tried to give it an anaesthetic injection. His attacker is one of a pair of Nile crocodiles kept at Shoushan zoo. Nile crocodiles are known to be man-eaters, but are also listed as an endangered species. (Photo by Frank Lin/Reuters)

A woman attempts to cover a tear gas canister fired by police at a crowd in Srinagar protesting against the recent killings in Kashmir, August 17, 2016. (Photo by Cathal McNaughton/Reuters)

A soldier walks on the bank of the river in central Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)

A participant in costume and make-up poses for a photo during a Halloween parade at Walibi park in Wavre, Belgium, October 31, 2018. (Photo by Yves Herman/Reuters)

Horses are spooked as the Woolsey Fire moves through the property on Cornell Road near Paramount Ranch on November 9, 2018 inAgoura Hills, California. About 75,000 homes have been evacuated in Los Angeles and Ventura counties due to two fires in the region. (Photo by Matthew Simmons/Getty Images)

A young woman dances in a field of tulips in a park in central Moscow on May 10, 2019. Moscow enjoys a heatwave while the rest of Europe struggles with cold weather. (Photo by Mladen Antonov/AFP Photo)