A girl carries a bag of recyclable items she collected from a landfill on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

An employee operates a machine while attaching a lock to a silver chain at the jewelry department of the Krastsvetmet non-ferrous metals plant, one of the world's largest producers in the precious metals industry, in the Siberian city of Krasnoyarsk, Russia, December 14, 2016. (Photo by Ilya Naymushin/Reuters)

Residents of the Huachipa populous district, east of Lima, are helped on March 17, 2017, by police and firemen rescue teams to cross over flash floods hitting their neighbourhood and isolating its residents. The climatic phenomenon El Niño is causing muddy rivers overflows on the entire Peruvian coast, isolating hundreds of people, mostly residents of Lima's industrial belt neighbourhoods. (Photo by Cris Bouroncle/AFP Photo)

LONDON - JUNE 04: A piece entitled “Entrance into wood” by Elke Krystufek goes on show at The Royal Academy Summer Exhibition on June 4, 2008 in London. In it's 240th year, the exhibition displays a wide range of recent work by both established and emerging artists. 10,000 artists submitted work for selection this year. (Photo by Peter Macdiarmid/Getty Images)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

A four-year-old bulldog named Goldie wearing spectacles and a nightcap. (Photo by Fox Photos/Getty Images). 9th January 1960

Guests on the terrace of Shepheard's Hotel, Cairo, circa 1940. (Photo by Hulton Archive/Getty Images)

A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925