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)

A woman photographs a Norwegian spruce Christmas tree from Oslo after it was lit at Trafalgar Square in central London, December 4, 2014. (Photo by Toby Melville/Reuters)

A boy fires confetti poppers as he participates in a procession to mark Eid-e-Milad-ul-Nabi, the birthday celebration of Prophet Mohammad, in Mumbai January 4, 2015. (Photo by Danish Siddiqui/Reuters)

A man walks past an overturned car in the street that was damaged in flooding caused by torrential rain in Cannes, France, October 4, 2015. (Photo by Eric Gaillard/Reuters)

The FFZero1 by Faraday Future is displayed at CES Unveiled, a media preview event for CES International Monday, January 4, 2016, in Las Vegas. The high performance electric concept car was unveiled during a news conference by Faraday Future. (Photo by Gregory Bull/AP Photo)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

A boy takes a picture of a car crash in Shenzhen, Guangdong province, August 4, 2014. Two passengers were sent to hospital but no death was reported as a result of the accident, according to local media. (Photo by Reuters/Stringer)

A member of a Chinese opera troupe applies make-up before performing at a shrine during the annual vegetarian festival in Bangkok, Thailand, on October 4, 2016. (Photo by Athit Perawongmetha/Reuters)