Participants of an unauthorized opposition rally gather in Tverskaya street in central Moscow on June 12, 2017. Authorities detained Russian opposition politician Alexei Navalny and hundreds of his supporters on Monday, as they mounted demonstrations across the nation against government corruption. Over 200 were detained in Moscow and Saint Petersburg an hour into the protest, according to an NGO that tracks arrests, with Navalny himself picked up by police in his building as he was headed to the event. (Photo by Vasily Maximov/AFP Photo)

Members of the “Avalon” team wearing 14th century knight costumes fight against each other on the bank of the Yenisei River during the regional amateurs tournament of clubs of historical reconstruction, “The Battle of the Nations 2015. Siberia”, in Krasnoyarsk January 24, 2015. (Photo by Ilya Naymushin/Reuters)

ESA astronaut Samantha Cristoforetti on the International Space Station 3 February 2015 during her Futura mission. Samantha is living and working on the Station as part of the Expedition 42 crew. Picture released on February 10, 2015. (Photo by ESA/NASA)

A performer takes part in the opening of the Temple Fair, part of Chinese New Year celebrations at Ditan Park, also known as the Temple of Earth, in Beijing, February 18, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Vietnamese military personnel in traditional dress take part in a parade celebrating the 40th anniversary of the end of the Vietnam War which is also remembered as the fall of Saigon, in Ho Chi Minh City, Vietnam, Thursday, April 30, 2015. (Photo by Dita Alangkara/AP Photo)

Cheering The News of Germany's Surrender New Yorkers Gather around a youth wearing a mask of Adolf Hitler to cheer the news of the Surrender of Germany on May 7. The Crowd is gathered in times Square, New York. May 08, 1945. (Photo by New York Post/Photo Archives, LLC via Getty Images)

Dancers perform during the Opening Ceremony of the Rio 2016 Olympic Games at Maracana Stadium on August 5, 2016 in Rio de Janeiro, Brazil. (Photo by Jamie Squire/Getty Images)

Festival-goers wash on Shipyard Island, the venue of the 24th Sziget (Island) Festival in Northern Budapest, Hungary, 15 August 2016. The venue, one of the biggest cultural events of Europe, offers art exhibitions, theatrical and circus performances and above all music concerts from 10 to 17 August. (Photo by Szabó Gábor/Origo.hu)