A girl walks in front of a graffiti painted on the wall of a house located inside the 15th-century complex built by Mameluk Sultan al-Ashraf Qaitbey, in Cairo's City of the Dead, Egypt February 13, 2017. (Photo by Amr Abdallah Dalsh/Reuters)

Adventurer Sam Cossman movies towards the huge lava lake wearing a custom built industrial proximity heat suit on December 20, 2014 in Ambrym, Vanuatu. (Photo by Conor Toumarkine/Barcroft Media)

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)

A demonstrator dressed as Santa Claus holds up a flag as a riot police vehicle releases a jet of water during a protest against the private system of pension fund administrators in Santiago, Chile, December 10, 2015. The flag reads “Classist Workers Union”. (Photo by Ivan Alvarado/Reuters)

Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

People protest at the Boston Free Speech Rally in Boston, USA on August 19. 2017. With the Boston Free Speech rally was closed to the media (despite the Boston Common being a public space), a lot of the media’s coverage centred on the tensions within the larger counter-protest. (Photo by Stephanie Keith/Reuters)

Festival crowd enjoying the weather on Day 1 of Reading Festival on August 25, 2017 in Reading, England. (Photo by Dean Fardell/Barcroft Images)

A massive, 8 metre tall sculpture of Marilyn Monroe, frozen with her dress blowing up, was on display at a shopping mall in downtown Dalian city, northeast China's Liaoning province, on Tuesday, November 14, 2017. The sculpture is a replica of Seward Johnson's Forever Marilyn in Chicago. (Photo by Imagine China/Rex Features/Shutterstock)