A serviceman kisses the main icon for the Russian Armed Forces' main cathedral, delivered at the Church of Our Lady the Healer in Rostov-On-Don, Russia on May 15, 2018. The Russian Armed Forces' main cathedral is to be built in Patriot Military Park in Kubinka outside Moscow by 2020, the year of the 75th anniversary of the victory of the Soviet Red Army over Nazi Germany in the 1941-45 Great Patriotic War, the Eastern Front of World War II. (Photo by Valery Matytsin/TASS)

A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)

Syrian fighters from the Turkish-backed National Liberation Front (NLF) fire a missile against regime positions on May 13, 2019 in the rebel-held northern part of Syria's Hama province. Clashes on the edge of a jihadist bastion in northwestern Syria have killed at least 42 fighters in 24 hours, a monitor said today, after regime bombardment on the region devastated health services. (Photo by Omar Haj Kadour/AFP Photo)

A participant takes part in a high heel race to protest in favor of gender equality in Monterrey, Mexico on May 12, 2019. (Photo by Daniel Becerril/Reuters)

Marina performs on stage at O2 Apollo Manchester on May 10, 2019 in Manchester, England. (Photo by Andrew Benge/Redferns)

A young woman dances in a field of tulips in a park in central Moscow on May 10, 2019. Moscow enjoys a heatwave while the rest of Europe struggles with cold weather. (Photo by Mladen Antonov/AFP Photo)

A Vietnamese cosplayer poses as police officer character from the game during the League of Legends (LOL) Mid-Season Invitational 2019 play-in group stage, in GG Stadium, Ho Chi Minh, Vietnam May 5, 2019. (Photo by Reuters/Kham)

A Sotheby's employee poses with a claw-set diamond ring weighing 36.57 carats during a press preview of an upcoming auction from Sotheby's in Geneva, Switzerland, 08 May 2019. The ring is expected to reach between 4,500,000 to 5,500,000 US Dollars during the “Magnificent Jewels and Noble Jewels” auction on May 14 in Geneva. (Photo by Valentin Flauraud/EPA/EFE)