A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

Couples take part in a Valentine's Day attempt to break the record for the world's largest simultaneous gay kiss on February 14, 2004 in Rome, Italy. (Photo by Franco Origlia/Getty Images)

Riot police walk in the street as a couple kiss on June 15, 2011 in Vancouver, Canada. Vancouver broke out in riots after their hockey team the Vancouver Canucks lost in Game Seven of the Stanley Cup Finals. (Photo by Rich Lam/Getty Images)

British reality TV personality Scotty T (Scott Timlin) partied at the Aruba Nightlcub in Redcar, England last night, June 11, 2018 and fans couldn't wait to see his new Tattoo. Scotty just whipped down his kegs and showed anyone who asked, with a queue of 200 girls it was quite a night. One girl asking to kiss his bottom whilst most just wanted a glimpse of his new Stephen Bear Tattoo. (Photo by Blackburn/Backgrid)

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)

Same-sеx marriage supporters kiss outside the Legislative Yuan Friday, May 17, 2019, in Taipei, Taiwan after the legislature passed a law allowing same-sеx marriage in a first for Asia. The vote Friday allows same-sеx couples full legal marriage rights, including in areas such as taxes, insurance and child custody. (Photo by Chiang Ying-ying/AP Photo)