A illegal gold miner of Kamoro people, Tinus, pan for gold on February 4, 2017 in Timika, Papua Province, Indonesia. Indonesia produces over 70 billion dollars in gold a year and is home to the largest gold mine and the third largest copper mine in the world, the Grasberg mine, which is located at West Papua. (Photo by Ulet Ifansasti/Getty Images)

Students training to be flight attendants hold books on their heads, chopsticks in their mouths, and papers in between their knees, as they take part in a standing posture practice at a vocational school in Shijiazhuang, Hebei province, China May 4, 2017. (Photo by Reuters/Stringer)

A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)

A model presents a creation by Singapore-born designer Andrew GN as part of his Fall/Winter 2016/2017 women's ready-to-wear collection show in Paris, France, March 4, 2016. (Photo by Benoit Tessier/Reuters)

An employee looks at the artwork “4-Chlorephenol, 2008”, part of the artist Damien Hirst's exhibition “The Complete Spot Paintings” at the Gagosian Gallery on January 12, 2012 in London, England. (Photo by Matthew Lloyd/Getty Images)

Swimmers in fancy costume take part in the New Year's Day swim at Saundersfoot in Wales, Britain, January 1, 2017. (Photo by Rebecca Naden/Reuters)

The two Pulis Quastie and Gin-Gin run in the snow in their garden in Lautertal, southern Germany, Thursday, January 5, 2017. (Photo by Michael Probst/AP Photo)

Drivers take part in a demolition derby organised by the Malta Motor Sports Association to raise funds for charity in Ta' Qali, outside Valletta, Malta, January 8, 2017. (Photo by Darrin Zammit Lupi/Reuters)