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 model wearing a creation by Luis Benitez poses during an urban shoot as part of Andalucia de Moda (Andalusia Fashion) at the aquarium of Seville, southern Spain, November 11, 2015. (Photo by Marcelo del Pozo/Reuters)

Fighters of the pro-government Popular Resistance Committees militia carry a cannon as they transport it in parts to Yemen's southwestern war-torn city of Taiz December 26, 2015. (Photo by Reuters/Stringer)

A man with a mask poses for a portrait as he takes part in festivities in honour of patron saint San Jeronimo in Masaya city, Nicaragua November 20, 2016. (Photo by Oswaldo Rivas/Reuters)

Revellers take part in the 21st Rio LGBT pride parade at Copacabana beach in Rio de Janeiro, Brazil, on December 11, 2016. (Photo by Yasuyoshi Chiba/AFP Photo)

A biplane taking part in the Vintage Air Rally lands, in Stellenbosch, near Cape Town, South Africa December 16, 2016. (Photo by Mike Hutchings/Reuters)

Women take a selfie next to a police officer as they take part in New Year's Eve celebrations in the Bund, in Shanghai, China December 31, 2016. (Photo by Aly Song/Reuters)

A model presents creations by designer Filipe Faisca as part of his Spring/Summer 2017 collection show during Lisbon Fashion Week, Portugal, October 9, 2016. (Photo by Rafael Marchante/Reuters)