Internally displaced Syrian children stand at the entrance of their makeshift shelter that is an underground cave in Om al-Seer, southern Idlib countryside, Syria December 26, 2015. (Photo by Khalil Ashawi/Reuters)

In this Sunday June 13, 1988 file photo West German police officers arrest an English soccer hooligan who sticks out his tongue. Rioting broke out between some 100 hooligans and the police in downtown Stuttgart, West Germany following the European Soccer Championships match between England and Ireland. England was defeated by Ireland 0-1. (Photo by Kraufmann/AP Photo/File)

Miguel Toribio, 11, puts a pistol belonging to his father into his belt, before demonstrating newly learnt skills from military-style weapons training, to a Reuters journalist in Ayahualtempa, Mexico, February 3, 2020. (Photo by Alexandre Meneghini/Reuters)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

Children feeding the birds in this Victorian Christmas greetings card. (Photo by Hulton Archive/Getty Images). Circa 1885

A baby bush-baby in a set of scales at London Zoo shortly after birth. (Photo by Fox Photos/Getty Images). 10th August 1938

A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. (Photo by David Ryder/Reuters)