Couples take part in a competition during a mass wedding of 64 doctoral student couples at Harbin Institute of Technology, a university in Harbin, Heilongjiang province, China, June 4, 2017. (Photo by Reuters/Stringer)

Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

Mongolia's Olympic wrestler Battsetseg Soronzonbold (front) fights with her training partner during a daily training session at the Mongolia Women’s National Wrestling Team training centre in Bayanzurkh district of Ulaanbaatar, Mongolia, July 1, 2016. Battsetseg Soronzonbold became a national hero in her native Mongolia after winning wrestling bronze at the London Olympics and is determined to turn the medal into gold in Rio next month. (Photo by Jason Lee/Reuters)

A minaret, that was damaged during fighting between Islamic State jihadists and government forces, is seen in Ben Guerdane, near the Libyan border, Tunisia April 10, 2016. After a U.S. air strike killed a Tunisian jihadist commander in western Libya in late February, dozens of Islamic State fighters sneaked across the border into Tunisia and attacked an army barracks and police bases in the town of Ben Guerdane. (Photo by Zohra Bensemra/Reuters)

A zookeeper wearing orangutan costume tries to escape while zookeepers hold up a net in an attempt to capture it during an Escaped Animal Drill at Tama Zoological Park in Tokyo, Japan on February 22, 2019. The annual escape drill is held to train zookeepers what to do in the event of an animal escape. This year a member of staff wearing an orangutan costume was captured and subdued with large nets, sticks and tranquilizer guns to make sure the orangutan did not get away. (Photo by Rodrigo Reyes Marin/ZUMA Wire/Alamy Live News)

Anthony Joshua, right, knocks down Andy Ruiz during the third round of a heavyweight championship boxing match Saturday, June 1, 2019, in New York. Ruiz won in the seventh round. (Photo by Frank Franklin II/AP Photo)

Street artist Irony’s mural of a young woman on Jamaica Street in Liverpool, UK on September 22, 2019. The city has recently been transformed with bold murals painted by local artists on walls and buildings. Recognisable faces including those of the Beatles, Jürgen Klopp and Stephen Hawking. (Photo by Peter Byrne/PA Wire Press Association)