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)

Joaldunaks return in a trailer to their town at the end of Carnival between of the Pyrenees villages of Ituren and Zubieta, northern Spain, Monday, February 1, 2016. In one of the most ancient carnivals in Europe, dating from before the Roman empire, companies of Joaldunak (cowbells) made up of residents of two towns, Ituren and Zubieta, parade the streets costumed in sandals, lace petticoats, sheepskins around the waist and shoulders, coloured neckerchiefs, conical caps with ribbons and a hyssop of horsehair in their right hands and cowbells hung across their lower back. (Photo by Alvaro Barrientos/AP Photo)

Cardboard cut outs of the faces of three candidates for the Republican nomination for the 2016 US Presidential election (L-R) Ted Cruz, Donald Trump and Marco Rubio, are seen set up on urinals in a pub in London on March 1, 2016 as part of an informal poll for customers to log which they dislike the most. Part of the satirical television show The Last Leg, customers at the pub are able to choose which urinal to use and then log their poll on a list on the wall afterwards. (Photo by Justin Tallis/AFP Photo)

A life-size robot named “Mark 1”, built by product and graphic designer Ricky Ma, 42, is seen in Hong Kong, China March 31, 2016. Ma, a robot enthusiast, spent a year-and-a half and more than HK$400,000 ($51,000) to create the humanoid robot, which is modelled after a Hollywood star, to fulfil his childhood dream. The eyes of the robot include face and color tracking functions. (Photo by Bobby Yip/Reuters)

In this May 1, 2016 photo, a reluctant donkey is alternately pushed and pulled and enticed with carrots toward town hall in order to be dressed for the costume competition at the annual donkey festival in Otumba, Mexico state, Mexico. Otumba was an important donkey market during Spanish colonial times, standing at the crossroads of major roads leading to Mexico City, where the beasts pulled heavy loads and carried travelers. Today, however, farmers use tractors and pickup trucks, and the donkey population is in decline. (Photo by Rebecca Blackwell/AP Photo)

Unsettled life in Europe failed to change the slow pace of life on the Isle of Capri, off Naples, Italy. Some of the socialites who have come there to relax enjoy an aquatic luncheon serviced in the cool Mediterranean, September 1, 1939. Swimming waiters push out the floating tables bearing meals which include wine and spaghetti. In the background are the rocks of Faraglioni. (Photo by Hamilton Wright/AP Photo)

One-year-old female giant panda cub Nuan Nuan reacts inside her enclosure during joint birthday celebrations for the panda and its ten-year-old mother Liang Liang at the National Zoo in Kuala Lumpur on August 23, 2016. Giant pandas Liang Liang, aged 10, and her Malaysian-born cub Nuan Nuan, 1, were born on August 23, 2006 and August 18, 2015 respectivetly. (Photo by Mohd Rasfan/AFP Photo)