A US Army M1A2 SEP tank participates in the Strong Europe Tank Challenge 2017 at the military training area in Grafenwoehr, Germany, 12 May 2017. Six North Atlantic Treaty Organization (NATO) nations and partner nations, Austria, France, Germany, Poland, Ukraine and the USA are taking part in this competing exercise. (Photo by Christian Bruna/EPA)

A bishop walks past a new street-art collage by Italian artist Maupal showing Pope Francis playing tic-tac-toe and drawing peace signs as a Swiss guard keep watches the street near the Vatican on October 19, 2016 in Rome. (Photo by Tiziana Fabi/AFP Photo)

South Korean college students wearing masks hold up candles as they march after a rally calling for South Korean President Park Geun-hye to step down in Seoul, South Korea, Saturday, November 12, 2016. Hundreds of thousands of people flooded Seoul's streets on Saturday demanding the resignation of Park amid an explosive political scandal, in what may be South Korea's largest protest since it shook off dictatorship three decades ago. (Photo by Lee Jin-man/AP Photo)

Adolf Hitler (left), German Nazi politician, in a deck chair next to is niece Angela (Geli) Raubal – around 1930. (Photo by Ullstein Bild/Ullstein Bild via Getty Images)

In this November 2, 2018 photo, a voodoo believer who is supposed to be possessed with Gede spirit performs rituals near Baron Samedi's tomb during the annual Voodoo festival Fete Gede at Cite Soleil Cemetery in Port-au-Prince, Haiti. As a proof that they got into trance and their bodies got possessed by Gedes, they drink and wash their faces, their eyes and even their genitals with a mixture of raw rum and hot chili peppers that, according to believers, could burn the skin of any human alive. (Photo by Dieu Nalio Chery/AP Photo)

An Iran fan attends the Russia 2018 World Cup Group B football match between Morocco and Iran at the Saint Petersburg Stadium in Saint Petersburg on June 15, 2018. (Photo by Dylan Martinez/Reuters)

Cambridge students the morning after the Trinity and Jesus college May Balls in Cambridge, United Kingdom on June 19, 2018. Students at Cambridge University celebrate the end of the academic year with the May Balls. (Photo by South West News Service)

Iranian soccer fan wait for the start of the group B match between Iran and Spain at the 2018 soccer World Cup in the Kazan Arena in Kazan, Russia, Wednesday, June 20, 2018. (Photo by Diego Azubel/EPA/EFE)