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)

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)

The Vattenfall Solar Team car “Nuna” from the Netherlands competes in the Challenger class on Day 2 of the 2019 Bridgestone World Solar Challenge at Elliott on October 14, 2019 in Elliott Australia. Teams from across the globe are competing in the 2019 World Solar Challenge – a 3000 km solar-powered vehicle race between Darwin and Adelaide. The race starts on the 13th of October in Darwin in the Northern Territory and travels the Stuart Highway to Port Augusta and then via Highway 1 to finish in the City of Adelaide in South Australia. (Photo by Mark Evans/Getty Images for SATC)

In this picture taken on Thursday, December 1, 2016, an Iranian woman covers herself with a blanket due to the cold, while visiting Khour salt lake during her tour of the Mesr desert about 305 miles (500 kilometers) southeast of the capital Tehran, Iran. Deserts make up parts of Iran which have recently become tourist destination for young Iranians looking for a break on their weekend. The increase in tourists to the desert has stimulated economic growth in the area. (Photo by Ebrahim Noroozi/AP Photo)

Fireworks explode over the Kremlin in Red Square which was blocked by police during New Year celebrations in Moscow, Russia, Sunday, January 1, 2017. New Year's Eve is Russia's major gift-giving holiday, and big Russian cities were awash in festive lights and decorations. (Photo by Alexander Zemlianichenko Jr./AP Photo)

Sheep are waiting in Via Manzoni before the final filming of the Last Shepherd on October 1, 2011 in Milan, Italy. Directed by Marco Bonfanti, L'Ultimo Pastore (The Last Shepherd) tells the story of the life of Renato Zucchelli, the last nomadic shepherd in Milan. (Photo by Pier Marco Tacca/Getty Images)

An autumn leaf sticks to a bench near the Bishops Castle near Wells Cathedral on November 1, 2011 in Wells, England. According to a number of nature watchers the autumn colours are currently reaching their peak following an unusually warm September and October which has led to trees holding onto their leaves longer than normal. (Photo by Matt Cardy/Getty Images)

(L-R) Mollie King and Frankie Sandford of The Saturdays performs for a dress rehearsal before the first night of their “All Fired Up!” tour at The Bournemouth International Centre on December 1, 2011 in Bournemouth, United Kingdom. (Photo by Dave J. Hogan/Getty Images)