A tourist poses on the glass-bottom bridge at Zhangjiajie Grand Canyon on August 20, 2016 in Zhangjiajie, Hunan Province of China. The Zhangjiajie Grand Canyon's glass-bottomed bridge welcame its trial operation on Saturday and about 8,000 tourists crowded to view the grand glass bridge. (Photo by VCG/VCG via Getty Images)

Revellers dance at Notting Hill Carnival on August 29, 2016 in London, England. The Notting Hill Carnival, which has taken place annually since 1964, is expected to attract over a million people. The two-day event, started by members of the Afro-Caribbean community, sees costumed performers take to the streets in a parade and dozens of sound systems set up around the Notting Hill streets. (Photo by Jack Taylor/Getty Images)

Vehicles are burning as thousands of people take to the streets during the May Day demonstrations on May 1, 2018 in Paris, France. This month celebrates the 50th anniversary of May 68 when France seen millions of students and striking workers, come onto the streets in demonstrations that changed the country. (Photo by Jeff J. Mitchell/Getty Images)

Members of the Apollo Rainbow Dancers stretch out in special A train late on May 4, 1985, in New York. The legendary Apollo Theatre celebrated its 50th anniversary in an official reopening after a 15 month refurbishing with a celebrity studded evening. (Photo by Ray Stubblebine/AP Photo)

An Afghan hunter shoots at a duck in Laghman province, Afghanistan on May 30, 2018. (Photo by Reuters/Parwiz)

In this May 8, 2015 photo, sisters Zoraida Infante, left, and Graciela Trujillo pray on Fishermen's Beach before therapeutic swimming in the Pacific Ocean in Lima, Peru. Under overcast skies, the bathers practice thalassotherapy, which derives from the Greek “thalasso”, for “sea”, and draws on the ocean's healing properties. (Photo by Rodrigo Abd/AP Photo)

Wakhi nomad women milk yaks in Wakhan, Afghanistan. About 12,000 villagers live at an altitude of 4,500 metres in the harsh, desolate terrain. The Wakhi people live a simple, relaxed life with their livestock. (Photo by Eric Lafforgue/Barcroft Images)

Children play football in Bujumbura, Burundi on March 19, 2015. (Photo by Carl de Souza/AFP Photo)