A group of people are seen on a Victoria line train in London, England during the first night of the Night Tube service on August 19 2016. The Central line and Victoria line are the first to operate a Night service with further lines expected to be running by the end of the year. (Photo by SWNS.com)

A group of fashionable nonagenarians pose for a photo in Pengzhou, Sichuan, China on October 12, 2016. (Photo by Rex Features/Shutterstock)

A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

Shoppers walk past crocodiles for sale at a market in Bata on February 3, 2015. Markets in Equatorial Guinea sell a variety of animals including pangolins, monkeys and crocodiles as food. (Photo by Carl de Souza/AFP Photo)

An Afghan boy jumps off the turret of a Soviet tank on a hilltop on the the outskirts of Kabul, Sunday, March, 4, 2018. (Photo by Rahmat Gul/AP Photo)

Russia' s President Vladimir Putin (L) congratulates prizewinners at the 2018 Youth Judo Tournament dedicated to Soviet and Russian judo coach Anatoly Rakhlin, and held at St Petersburg' s Yubileyny Palace of Sports in St Petersburg, Russia on May 23, 2018. (Photo by Mikhail Metzel/TASS)

These men are chased by the defiant elephants on May 4, 2013. Taken by Biplab Hazra in Bishnupur, India, the images show the extreme lengths the inhabitants of the town go to to deter elephants from damaging their crops and property. Elephants encroaching out of their habitats is an increasingly common occurrence with deforestation in much of India. (Photo by Biplab Hazra/Caters News Agency)

Traffic lights feature illustrations of a homosexual couple in downtown Frankfurt Main, Germany, 18 July 2019. An annual gay pride parade will take place on 20 July 2019 in Frankfurt to commemorate Christopher Street Day (CSD). The event commemorates the riots that erupted following a police raid in 1969 at a gay bar on Christopher Street in Greenwich Village, New York City. (Photo by Armando Babani/EPA/EFE)