Couples take part in a competition during a mass wedding of 64 doctoral student couples at Harbin Institute of Technology, a university in Harbin, Heilongjiang province, China, June 4, 2017. (Photo by Reuters/Stringer)

Japanese chorus girls appear to be drilling in military tactics atop their theater building as they perform salutes, June 30, 1937. The officer is from the Japanese regular army and says the girls display more rhythm in their drills than do the regular troops. (Photo by AP Photo)

A man watches a wave hit a rock pool at Curl Curl beach as large swell hits the East Coast of Australia on June 6, 2016 in Sydney, Australia. Torrential rain over the weekend saw streets and homes flooded while wind gusts up to 120km per hour brought down trees and powerlines. A king tide has also seen beachside homes evacuated on Sydney's northern beaches as large waves erode the coast. (Photo by Cameron Spencer/Getty Images)

In this picture taken Thursday, August 4, 2016, seal Tristan looks out of a basket while being released into the North Sea together with others at the beach of the island Juist, Germany. He is part of the first group of released seals of the seal breeding station Norddeich this year. (Photo by Carmen Jaspersen/DPA via AP Photo)

2016 Rio Olympics, Rugby, Women's Semifinals Britain vs New Zealand, Deodoro Stadium, Rio de Janeiro, Brazil on August 8, 2016. Portia Woodman (NZL) of New Zealand tackles Claire Allan (GBR) of United Kingdom. (Photo by Phil Noble/Reuters)

Pfc. Remy Bouchard swaps a cigarette for an egg with a French Orphan near La Haye Du Puits, France on July 18, 1944, which was captured by American forces. The boy is only twelve years old. (Photo by Hugh Broderick/AP Photo)

People fight for the ball as they take part in a mud football match during a festival for celebrating harvest in a village in Jinhua, Zhejiang Province, China September 24, 2017. (Photo by Reuters/China Stringer Network)

A female sniper of the Syrian Democratic Forces (SDF) monitors the area during a celebration at the iconic Al- Naim square in Raqa on October 19, 2017, after retaking the city from Islamic State (IS) group fighters. The SDF fighters flushed jihadist holdouts from Raqa' s main hospital and municipal stadium, wrapping up a more than four- month offensive against what used to be the inner sanctum of IS' s self- proclaimed “caliphate”. (Photo by Bulent Kilic/AFP Photo)