School leavers celebrate their graduation in Moscow's Red Square in Moscow, Russia on June 20, 2019. (Photo by Artyom Geodakyan/TASS)

First Lady Melania Trump kisses Canada's Prime Minister Justin Trudeau next to the President Donald Trump during the family photo with invited guests at the G7 summit in Biarritz, France, August 25, 2019. (Photo by Carlos Barria/Reuters)

A member of staff at Morton & Eden holds an extremely rare early Islamic gold coin on Thursday September 12, 2019, which is expected to fetch £1.4m at auction in London. Measuring a 20mm across, about the size of a modern £1 piece, it is one of the world's rarest and most treasured Islamic gold coins from the first dynasty of Islam, the Umayyad gold dinar dated 105h (723AD). (Photo by Victoria Jones/PA Images via Getty Images)

A woman holds up an umbrella and license plates, one that reads “love”, during violent protests between riot police and demonstrators in the Causeway Bay district of Hong Kong on October 1, 2019. The city observes the National Day holiday to mark the 70th anniversary of communist China's founding Strife-torn Hong Kong on October 1 marked the 70th anniversary of communist China's founding with defiant “Day of Grief” protests and fresh clashes with police as pro-democracy activists ignored a ban and took to the streets across the city. (Photo by Nicolas Asfouri/AFP Photo)

An opposition activist clashes with the police during a march against Venezuelan President Nicolas Maduro held on May Day, in Caracas on May 1, 2017. Security forces in riot vans blocked off central Caracas Monday as Venezuela braced for pro- and anti- government May Day protests one month after a wave of deadly political unrest erupted. (Photo by Federico Parra/AFP Photo)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)

Ivanka Trump poses with Kristina Hilko, Lauren Shovlin, and Anna Nesbitt, members of the Girls of Steel Robotics initiative, at the Astrobotic Technology facility in Pittsburgh, Pennsylvania on August 14, 2018. (Photo by Jason Cohn/Reuters)

A peformance artist attends an election rally for Cameroon presidential candidate for the opposition Univers party, Cabral Libii in Yaounde, Cameroon 06 October 2018. Africa's oldest president Paul Biya who has been in power since 1982 is up against eight candidates when voters go to the polls 07 October 2018. 6.9 million registered voters will head to the polls but marginalised anglophone separatists in the North West and South West of the country threaten to disrupt the elections. (Photo by Nic Bothma/EPA/EFE)