Venezuela's acting President and presidential candidate Nicolas Maduro kisses a painting of late Venezuelan president Hugo Chavez during a campaign rally in the state of Vargas April 9, 2013. Venezuelans will hold presidential elections on April 14. Maduro promised on Tuesday to hike Venezuela's minimum wage by about 40 percent if he is elected in a weekend vote to replace late socialist leader Chavez. (Photo by Carlos Garcia Rawlins/Reuters)

Tourists kissing front of Malaysia's landmark Petronas Twin Towers with lights on before turned off to mark Earth Hour 2016 in Kuala Lumpur, Malaysia, 19 March 2016. Earth Hour takes place worldwide at 8.30 p.m. local time and is a global call to turn off lights for 60 minutes to raise awareness of the danger of global climatic change (Photo by Fazry Ismail/EPA)

Performers in costume kiss as they take part in the carnival on the main Parade day of the Notting Hill Carnival in west London on August 27, 2018. Nearly one million people are expected by the organizers Sunday and Monday in the streets of west London' s Notting Hill to celebrate Caribbean culture at a carnival considered the largest street demonstration in Europe. (Photo by Daniel Leal-Olivas/AFP Photo)

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

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

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

Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)