Participants hang from ropes as they learn how to use safety gears at an experience centre for construction safety training in Beijing, September 5, 2014. The centre which opened in June 2014 was established to educate workers about construction safety. According to the centre, about 1,000 construction workers undergo 3-hour classes which comprises of 33 modules every month. (Photo by Kim Kyung-Hoon/Reuters)

West Berliners crowd in front of the Berlin Wall as they watch East German border guards demolish a section of the wall on November 11, 1989. (Photo by Gerard Malie/AFP Photo)

Iraqis run for cover as they flee Mosul's Al-Tayaran neighbourhood on February 28, 2017, during an offensive by Iraqi forces to retake the area from Islamic State (IS) group fighters. Hundreds of civilians fled through the desert to escape fighting and privation in Mosul, joining thousands of others who left their homes as conditions worsen in the city's west. (Photo by Ahmad Al-Rubaye/AFP Photo)

Iraqi women cry over their brother's body, who was killed by a mortar shell fired by Islamic State (IS) group jihadists on civilians who were gathered to receive aid, in Al-Risala neighbourhood on March 22, 2017, as an ongoing offensive by Iraqi forces to retake the city from the group continues. Iraqi forces launched a major operation to recapture west Mosul – the most-populated urban area still held by IS – on February 19, and have retaken a series of neighbourhoods from the jihadists. (Photo by Ahmad Al-Rubaye/AFP Photo)

TV and radio host Lizzie Cundy, 46, attends the World Premiere of “The Hatton Garden Job” at The Curzon Soho on April 11, 2017 in London, England. (Photo by Fame Flynet)

Aerobatic aircrafts fly during a performance at the Airshow Zhengzhou 2017 in Zhengzhou, capital of central China's Henan Province on April 27, 2017. The 5-day air show kicked off in Zhengzhou on Thursday, aiming to build a general aviation gathering center for business and communications. (Photo by Li An/Xinhua via ZUMA Wire)

St Andrews University students skinny dip in the sea as May Day celebrations in St Andrews, Scotland on April 30, 2017. Hundreds of revellers ditched their clothes and bravely jumped into the bitterly cold North Sea. (Photo by Alamy Stock Photos)

Actor Bella Thorne (L) and model Amber Rose at the NYLON Young Hollywood Party at AVENUE Los Angeles on May 2, 2017 in Los Angeles, California. (Photo by Joe Scarnici/Getty Images for NYLON)