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)

U.S. President Donald Trump gestures during his visit to a section of the U.S.-Mexico border wall in Otay Mesa, California, U.S. September 18, 2019. Trump threatened to do “dastardly things” to Iran in response to the drone attacks on the world’s largest oil plant in Saudi Arabia. The US President indicated he is wary of involving America in another war in the Middle East – but he did not rule out a military attack. (Photo by Tom Brenner/Reuters)

A postman walks past an art work titled “Alphabetti Spaghett” by artist Alex Chinneck on Norborough Road in Sheffield, Yorkshire, England on September 26, 2019. (Photo by Danny Lawson/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)

A camel calf is seen among a herd in the desert near Dakhla in Morocco-administered Western Sahara, on October 13, 2019. In the Oued Eddahab desert in Western Sahara, Habiboullah Dlimi raises dairy and racing camels just like his ancestors used to, but with a little help from modern technology. While his animals roam free and are milked traditionally, by hand, at dawn and dusk, they are watched over by hired herders and Dlimi follows GPS coordinates across the desert in a 4X4 vehicle to reach them. (Photo by Fadel Senna/AFP Photo)

British singer and actress Rita Ora performs on the stage at Sporting Summer Festival in Monaco on Tuesday, August 7, 2018. (Photo by Andrew Timms/Rita Ora Instagram)

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 couple joke as they walk on the beach on August 22, 2018 in Wonsan, North Korea. (Photo by Carl Court/Getty Images)