An opposition supporter gestures with a knife during clashes with police in Kibera slum in Nairobi, Kenya on October 26, 2017. Kenyans trickled into polling stations today for a repeat election that has polarised the nation, amid sporadic clashes as supporters of opposition leader ignored his call to stay away and tried to block voting. (Photo by Goran Tomasevic/Reuters)

Students pose for a picture with a 3- D optical illusion artwork of a devastated cityscape in Aleppo, Syria at the campus of the Meiji University in Tokyo on November 18, 2016. The Japanese branch of the human rights organisation Amnesty International displayed the artwork to encourage people to think about the Syrian civil war. (Photo by Toshifumi Kitamura/AFP Photo)

A woman sorts tobacco leaves at the Cohiba cigar factory “El Laguito” in Havana September 10, 2012. (Photo by Desmond Boylan/Reuters)

28 year old Rupa has her hair shaven to donate to the Gods at the Thiruthani Murugan Temple November 10, 2016 in Thiruttani, India. Rupa donated her hair with the wish that her daughter's illness is cured. The process of shaving ones hair and donating it to the Gods is known as tonsuring. It is common for Hindu believers to tonsure their hair at a temple as a young child, and also to celebrate a wish coming true, such as the birth of a baby or the curing of an illness. The “temple hair”, as it's known, is then auctioned off to a processing plant and then sold as pricey wigs and weaves in the US, Europe and Africa. (Photo by Allison Joyce/Getty Images)

“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)

Worker Shi Shenwei pulls a wheelbarrow at the construction site of a Buddhist temple in the village of Huangshan, near Quanzhou, Fujian Province, China, September 28, 2016. For most construction workers, lunch is a welcome break to rest and refuel. Not for Shi Shenwei. the 23-year-old spends his midday break jumping and swinging through a maze of scaffolding poles, performing a fitness routine that has made him China's latest social media sensation. (Photo by Thomas Peter/Reuters)

Young cheetahs eat meat at The Cheetah Conservation Fund (CCF) center in Otjiwarongo, Namibia, on August 13, 2013. The CCF started breeding Anatolian livestock dogs to promote cheetah-friendly farming after some 10,000 big cats – the current total worldwide population – were killed or moved off farms in the 1980s. Up to 1,000 cheetahs were being killed a year, mostly by farmers who saw them as livestock killers. But the use of dogs has slashed losses for sheep and goat farmers and led to less retaliation against the vulnerable cheetah. (Photo by Jennifer Bruce/AFP Photo)

A supporter of “Si” vote cries after the nation voted “NO” in a referendum on a peace deal between the government and Revolutionary Armed Forces of Colombia (FARC) rebels, at Bolivar Square in Bogota, Colombia, October 2, 2016. (Photo by John Vizcaino/Reuters)