Pokot men carry a part of a carcass of a bull killed by a young man during an initiation ceremony in Baringo County, Kenya, January 20, 2016. Far from the bustling city of Nairobi, in an isolated corner of Kenya's Rift Valley, young men from the Pokot community spear a bull in a ceremony called Sapana that takes them into adulthood. (Photo by Siegfried Modola/Reuters)

A bakery worker rides a bicycle as he carries fresh bread on his head in Cairo, Egypt, February 9, 2016. (Photo by Asmaa Waguih/Reuters)

A dog walker on Longsands beach before sunrise in Tynemouth, UK on April 1, 2016. (Photo by Owen Humphreys/PA Wire)

A porter stands at the bottom of the Illimani mountain, on the outskirts of La Paz, Bolivia, April 16, 2016. For years, Lydia Huayllas, 48, has worked as a cook at base camps and mountain-climbing refuges on the steep, glacial slopes of Huayna Potosi, a 19,974-foot (6,088-meter) Andean peak outside of La Paz, Bolivia. But two years ago, she and 10 other Aymara indigenous women, ages 42 to 50, who also worked as porters and cooks for mountaineers, put on crampons – spikes fixed to a boot for climbing – under their wide traditional skirts and started to do their own climbing. (Photo by David Mercado/Reuters)

Francisco da Silva Vale, 61, cools off fish with ice produced on solar-powered ice machines at Vila Nova do Amana community in the Sustainable Development Reserve, in Amazonas state, Brazil, September 23, 2015. Three solar-powered machines, are producing about ninety kilos of ice per day, in a region with poor access to electric energy, which used to be produced only with diesel oil, in the Amazon rain forest. (Photo by Bruno Kelly/Reuters)

A U.S. Army B-24 Liberator Bomber is hailed by a ground crewman as it takes off over a line of shark- nosed fighter planes at an advanced base in China on a mission on October 10, 1943, to bomb Japanese installations. (Photo by AP Photo)

A man carries a dog and wades through a flooded street in Chennai, in the southern Indian state of Tamil Nadu, Wednesday, December 2, 2015. Weeks of torrential rains have forced the airport in the state capital Chennai to close and have cut off several roads and highways, leaving tens of thousands of people stranded in their homes, government officials said Wednesday. (Photo by AP Photo)

Labourers load a three-wheeled vehicle onto the back of a van at the Mercato market in Addis Ababa October 9, 2015. Addis Ababa's “Mercato” – Italian for “market” – is reputedly the biggest open-air market in Africa, lying in the west of the capital. (Photo by Tiksa Negeri/Reuters)