Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

Two young women, having enjoyed a drink at a party, dance together in Tehran, Iran. Although unrelated men and women are forbidden to socialise together many people ignore these strictures in the privacy of their own homes. (Photo by Hossein Fatemi/Reuters/Panos Pictures/Courtesy of World Press Photo Foundation)

An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

Miners work extremely long days under the hot sun and the hours are often longer in illegal mines in Ghana, West Africa, 2014. An Australian photographer has captured the harsh reality of illegal mining under the unforgiving sun with these Ghanaian miners. (Photo by Heidi Woodman/Barcroft Images)

Tourists pay a visit to Edradour distillery on March 26, 2012 in Pitlochry, United Kingdom. (Photo by Jeff J. Mitchell/Getty Images)

Measuring just five feet at its widest point, the ultra-thin home was unveiled in the Polish capital of Warsaw on Sunday, October 21, 2012. Photo: The Keret House is squeezed into the space between two apartment buildings in Warsaw. There's a four-inch gap between the apartment buildings to either side. A perforated steel facade was used to allow in more light. (Photo by Andrea Meichsner/The New York Times)

A Thai wildlife department official carries a long-tailed macaque to a cage at a village in Bangkok, Thailand, September 21, 2015. Thai authorities were relocating the long-tailed macaques on Monday to lessen conflicts with the local community. (Photo by Chaiwat Subprasom/Reuters)

A devotee offers oil lamps on top of his body as part of a ritual during Dashain, the biggest religious festival for Hindus in Bhaktapur, Nepal, October 22, 2015. Hindus in Nepal celebrate victory over evil during the festival by flying kites, feasting, playing swings, sacrificing animals and worshipping the Goddess Durga as well as other gods and goddess as part of celebrations held throughout the country. (Photo by Navesh Chitrakar/Reuters)