Rescue workers help the injured at the site of a multi-storey building collapse in the capital Nairobi, Kenya Sunday, January 4, 2015. The residential building in the Huruma neighborhood of Nairobi collapsed on Sunday and according to the Kenya Red Cross, a dozen people have so far been rescued but an unknown number are still feared trapped. (Photo by AP Photo)

Competitors take part in the International Medieval Combat Federation World Championships at Scone Palace on May 10, 2018 in Perth, Scotland. Thousands of visitors are expected to attend the crowning place of Scottish Kings, Scone Palace for the IMCF World Championships which has five hundred competitors and officials from all over the world, from the UK to as far afield as Australia, South Africa and Mexico. (Photo by Jeff J. Mitchell/Getty Images)

The worst drought in 40 years has a cruel grip on Somalia. A struggling young government and militant violence have compounded to bring crisis to 6.7 million lives. The town of Baidoa is facing some of the harshest conditions. Surrounded by territory controlled by al-Shabaab militants and amid ongoing attacks, 160,000 people have had to leave their farms and are surviving in camps where hunger, thirst and cholera await them. (Photo by Peter Caton/Mercy Corps)

Sebastião Salgado is a Brazilian documentary photographer living in Paris. He has produced several books, and his work has been exhibited extensively around the world. His latest work, «Genesis», premieres at The Natural History Museum in London on April 11, on view through September 8, 2013. Photo: On South Georgia, a barren island in the far South Atlantic, a pair of southern elephant seal calves beckon before a colony of king penguins. “The male seals can grow to almost five tons,” says Salgado, “but these are just babies. This one looked at me with beautiful eyes”. (Photo by Sebastião Salgado/Amazonas/Contact Press Images)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)

A woman buys bread at a bakery in Cairo, January 8, 2015. The successful roll-out so far of a new “smart card” system to distribute subsidised bread has been a major achievement for Egypt's government, saving money while earning praise from families who no longer have to wake early to fight for loaves. (Photo by Mohamed Abd El Ghany/Reuters)

A knife is seen beside a bowl containing blood after a ram was killed as a sacrifice in front of a shrine at the annual voodoo festival in Ouidah, Benin, January 10, 2016. In Ouidah, a small town and former slave port in the West African country of Benin, the annual voodoo festival gathers visitors from far and wide. It's a week that brings together priests and dignitaries, rich and poor, locals and visitors from as far afield as the Caribbean and France. The festival commemorates the estimated 60 million people who lost their homelands and their freedom during the African slave trade. (Photo by Akintunde Akinleye/Reuters)

Mystical Forest. Tracey Jennings photographed this seven-gill shark in a kelp forest just off the shore of Simon's Town near Cape Town, South Africa. You don't need to travel far from cities to visit Narnia. This 7 gill shark was photographed in a kelp forest just off the shore of Simonstown near Cape Town, South Africa. (Photo by Tracey Jennings/National Geographic Travel Photographer of the Year Contest)