World Champion Trials bike rider Jack Field of Australia poses after performing the highest backflip on a motorcycle ever recorded as he flips his motorbike upside down on the roof of Melbourne's Eureka Tower (297.3 metres) during a AUS-X Open media opportunity at Eureka Tower on May 22, 2019 in Melbourne, Australia. The largest international Supercross and action sports event in the world outside of the USA, the AUS-X Open will be held at Melbourne's Marvel Stadium on November 30 2019. (Photo by Scott Barbour/Getty Images)

An Indian Royal Bengal tiger looks on at an enclosure on World Tiger Day at Alipore Zoo, Kolkata, India, 29 July 2019. Kolkata zoo authority added a new Tiger to the zoo for the visitors to mark the Tiger Day. Students of Kolkata are also taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA/EFE)

Swiss grass skier Stefan Portmann in action during a free practice at the Grasski World Championships in Marbach, Switzerland, 13 August 2019. About 80 participants from 10 nations will start at the Grasski - World Championships, which will take place from 13th to 18th August 2019. (Photo by Alexandra Wey/EPA/EFE)

An aircraft passes the rising sun during take off at the international airport in Frankfurt, Germany, Monday, September 2, 2019. (Photo by Michael Probst/AP Photo)

In this Tuesday, August 27, 2019, file photo, a climber stops to take pictures of clouds while climbing towards the summit of Mount Fuji to watch the sunrise, in Japan. (Photo by Jae C. Hong/AP Photo/File)

Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Turkana tribesmen walk with guns to protect their cattle from rival tribes near Baragoy, Kenya August 4, 2017. (Photo by Goran Tomasevic/Reuters)

Spectators pass through security screening ahead of the New Year's Eve celebration in Times Square in New York, on Sunday, December 31, 2017. (Photo by Peter Morgan/AP Photo)