An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

Bulls fight during the annual Bullfighting Festival on March 17, 2010 in Cheongdo, South Korea. More than 130 bulls from South Korea and abroad charge and lock horns in the annual festival which was run March 21, 2010. The bulls are grouped into three weight categories and fight head on until one of the bulls turns its head and runs away. (Photo by Chung Sung-Jun/Getty Images)

South Korea's Black Eagles aerobatics team perform a maneuver during a preview of the Singapore Airshow at Changi exhibition center in Singapore February 14, 2016. The Airshow will take place from February 16-21. (Photo by Edgar Su/Reuters)

Buddhists carry a dragon-shaped lantern during a lotus lantern parade in celebration of the upcoming birthday of Buddha in Seoul, South Korea, May 7, 2016. (Photo by Kim Hong-Ji/Reuters)

South Korean singer CL performs during the closing ceremony of the 2018 Winter Olympics in Pyeongchang, South Korea, Sunday, February 25, 2018, after 17 days of hard- fought competition. Olympic fire went out. (Photo by Natacha Pisarenko/AP Photo)

A visitor takes a selfie with a backdrop of sunflowers in full bloom at the E-World Sunflower Garden in Daegu, 237 kilometers southeast of Seoul, South Korea, 13 July 2024. (Photo by Yonhap/EPA)

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

Israeli soldiers get ready to launch the Skylark drone during a drill on January 16, 2012 near Bat Shlomo, Israel. (Photo by Uriel Sinai/Getty Images)