In this February 14, 2019 photo, a newlywed couple kisses while posing for photos at one of several free sets placed for newlyweds to take cell phone photos of themselves following a mass wedding ceremony on Valentine's Day in Mexico City. Hundreds of couples of all ages, many with their children, gathered to legally tie the knot in a mass ceremony in the capital's Venustiano Carranza neighborhood. (Photo by Rebecca Blackwell/AP Photo)

Andy Goldfarb, a staff biologist at the Point Defiance Zoo & Aquarium, plays with one of the four clouded leopard cubs currently at the zoo Friday, June 5, 2015 in Tacoma, Wash. The quadruplets were born on May 12, 2015 and now weigh about 1.7 lbs. each. Friday was their first official day on display for public viewing, usually during their every-four-hours bottle-feeding sessions, which were started after the cubs' mother did not show enough interest in continuing to nurse them. (AP Photo/Ted S. Warren)

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

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)

An Iraqi special forces soldier shot dead an Islamic State suicide bomber in Mosul, Iraq March 3, 2017. (Photo by Goran Tomasevic/Reuters)

Taliban soldiers ride bumper cars at an amusement park in Kabul, Afghanistan on September 13, 2021. (Photo by WANA via Reuters)