A passenger waits after his train arrived in Nouadhibou, Mauritania’s second largest city and the main export port for the country’s iron ore industry, on June 25, 2014. The mining company’s employees proudly call their firm the lung of their nation's economy and the train that ferries the ore to the coast stretches some two kilometres, making it one of the world's longest. SNIM mines black iron ore in the northern town of Zouerate, a remote desert location which nevertheless attracts people from all over the country looking for work. (Photo by Joe Penney/Reuters)

Models promote the game “Diamond Dogs” during the Gamescom 2015 fair in Cologne, Germany August 5, 2015. Hundreds of thousands of visitors will enjoy one of the world's largest computer and video game events until Sunday. (Photo by Kai Pfaffenbach/Reuters)

A group of children and their dog playing an Easter game in Cardiff. The game involves trying to eat an Easter egg off a piece of string without using their hands. (Photo by Richards/Fox Photos/Getty Images). 26th March 1937

A curious leopard cub toys with a camera at MalaMala Game Reserve in Mpumalanga Province, South Africa. (Photo by Barcroft Media)

A tourist carries her luggage in a flooded St. Mark's Square, in Venice, Wednesday, November 13, 2019. The high-water mark hit 187 centimeters (74 inches) late Tuesday, Nov. 12, 2019, meaning more than 85% of the city was flooded. The highest level ever recorded was 194 centimeters (76 inches) during infamous flooding in 1966. (Photo by Luca Bruno/AP Photo)

Passengers pose for a selfie as they wait for the Night Tube train service at Oxford Circus on the London underground system in London, Britain August 20, 2016. The London Underground is starting its first-ever overnight service, a move city leaders hope will make the British capital a truly 24-hour city and bolster the local economy. (Photo by Paul Hackett/Reuters)

A vendor carries her products in a bucket on her head as she walks through the neighborhood of Jalousie, in the commune of Petion Ville, Port-au-Prince, on December 17, 2018. On the hills of Port-au-Prince, a chaotic jumble of structures stretches ever farther into the distance: Haiti's capital is suffering under the weight of high inflation, endemic corruption and a perilous drop in the value of its currency. Jalousie is a poor neighborhood of the capital which lacks sanitation and potable water. (Photo by Hector Retamal/AFP Photo)

Crew in Britain's first ever full-size reconstructed sea-going Bronze Age boat, paddle out to sea near to the National Maritime Museum as it makes its maiden voyage on March 6, 2013 in Falmouth, England. (Photo by Matt Cardy)