A boy holds a machine gun at a military hardware exhibition during a swear-in ceremony for new recruits of the Russian military-patriotic club “Yunarmia” (Young army) in the Black Sea port of Sevastopol, Crimea, October 27, 2018. (Photo by Pavel Rebrov/Reuters)

Russia's President Vladimir Putin and Saudi Arabia's Crown Prince Mohammed bin Salman are seen during the G20 summit in Buenos Aires, Argentina November 30, 2018. G20 powers open two days of summit talks on Friday after a stormy buildup dominated by tensions with Russia and US President Donald Trump's combative stance on trade and climate fears. (Photo by Marcos Brindicci/Reuters)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)

An opposition fighter from the Failaq al-Rahman brigade fires a heavy machine gun in Jobar, a rebel-held district on the eastern outskirts of the Syrian capital Damascus, on March 19, 2017. (Photo by Amer Almohibany/AFP Photo)

A reveller catches beer thrown from a balcony during the opening day or “Chupinazo” of the San Fermin Running of the Bulls fiesta on July 6, 2017 in Pamplona, Spain. The annual Fiesta de San Fermin, made famous by the 1926 novel of US writer Ernest Hemmingway entitled “The Sun Also Rises”, involves the daily running of the bulls through the historic heart of Pamplona to the bull ring. (Photo by Pablo Blazquez Dominguez/Getty Images)

Confiscated rare and protected wildlife products such as these stuffed Sumatran tiger skins are burned and destroyed during a ceremony by government forestry and wildlife officials in Banda Aceh, Aceh province, Indonesia May 23, 2016 in this photo taken by Antara Foto. (Photo by Irwansyah Putra/Reuters/Antara Foto)

Female labourers wearing helmets take a break from laying underground electricity cables in Ahmedabad, India, March 7, 2016. (Photo by Amit Dave/Reuters)

A couple photograph The Helmsley Building on Park Avenue, lit in honor of the victims of the Nice attacks, in Manhattan, New York, U.S., July 15, 2016. (Photo by Brendan McDermid/Reuters)