Manson Gerasimov of Russia and Agustina Piaggio of Argentina, representing the city of Rio Grande, Argentina, perform during the Stage style final round at the Tango World Championship in Buenos Aires, Argentina on August 23, 2018. (Photo by Marcos Brindicci/Reuters)

Thailand’s Surasak Waenwiset tries a shot as Hungary’s Marcell Fenyvesi stands nearby, during their Beach Handball Men’s Tournament match in Tecnopolis Park, during the Youth Olympic Summer Games in Buenos Aires, Argentina on October 9, 2018. (Photo by Florian Eisele/AP Photo)

MiG-15 jet fighters are pictured in Kucova Air Base in Kucova, Albania on October 3, 2018. Albania retired its 224 Soviet- and Chinese-made MiGs in 2005, and since 2009 NATO neighbors Italy and Greece monitor its airspace. That led to economic decline in and around Kucova, which was called “Stalin City” during the era of Communist rule. (Photo by Florion Goga/Reuters)

The Swiss Air Force Patrouille Suisse aerobatic team performs during the men's downhill race at the Alpine Skiing FIS Ski World Cup in Wengen, Switzerland, Saturday, January 19, 2019. (Photo by Anthony Anex/Keystone via AP Photo)

A Russian ground staff member signals to the pilot of a Sukhoi Su-25 fighter jet at the Hmeymim air base near Latakia, Syria, in this handout photograph released by Russia's Defence Ministry October 22, 2015. (Photo by Reuters/Ministry of Defence of the Russian Federation)

A woman wearing a traditional "mantilla" dress takes part in an open-air mass to celebrate Madrid's patron saint La Almudena Virgin in Madrid, Spain, November 9, 2015. (Photo by Susana Vera/Reuters)

The Vietnam Slide Project was created by photo editor Kendra Rennick, who began collecting photo slides after a close friend lost her father, a Vietnam veteran. Her friend found a box of slides that her father had taken while in Vietnam and from there Rennick has continued to collect photographs that Vietnam veterans took during their tours of duty. Here: A photo taken from the collection of D.Thornton, who served in the First Air Cavalry division of the United States Army. (Photo by D.Thornton/The Vietnam Slide Project)

A man carries a blood stained stretcher in a site hit by what activists said were airstrikes carried out by the Russian air force in the town of Douma, eastern Ghouta in Damascus, Syria January 10, 2016. (Photo by Bassam Khabieh/Reuters)