In this March 22, 1975 file photo, a refugee clutches a baby as a government helicopter gunship carries them away near Tuy Hoa, Vietnam, 235 miles northeast of Saigon. They were among thousands fleeing from Communist advances. AP Photographer Nick Ut will be retiring from the AP in March 2017 after 51 years of taking photographs from the front lines of the Vietnam War to the red carpets of Hollywood. (Photo by Nick Ut/AP Photo)

Syrian Tulin Hashemi waits for a job interview at a hotel in Vidigal slum in Rio de Janeiro, Brazil, September 22, 2015. Tulin, whose mother arrived two days ago, has been living in Brazil for two months. As she does not speak Portuguese, Tulin says it is difficult for her to find a job and therefore she is staying at the slum as it is one of the cheaper neighbourhoods to live in. According to the National Committee for Refugees (CONARE), 2,077 people fleeing the Syrian civil war have settled in Brazil, whilst a quarter of the 8,400 refugees in the Latin American country come from Syria. (Photo by Pilar Olivares/Reuters)

Hadeel, 10, asks a passerby for help to pay a medical bill as her father Shahrour, 54, sits in his wheelchair in the Douma neighbourhood of Damascus Syria February 3, 2016. Shahrour said he developed diabetes at the beginning of the war in Syria. A lack of insulin led to his medical condition worsening and his right foot had to be amputated. Recently he also suffered a stroke that paralysed half his face. He and part of his extended family, a total of 18 people, live together and struggle to get by. (Photo by Bassam Khabieh/Reuters)

Historical re-enactor Andreas Wenzell dresses as Britain's King Richard the third in a living history camp during an anniversary event for the Battle of Bosworth near Market Bosworth in central Britain, August 23, 2015. The Battle of Bosworth took place in 1485 during the War of the Roses between the House of Lancaster and the House of York. King Richard III was defeated by Henry Tudor marking the end of Plantagenet rule and the beginning of the Tudor dynasty. (Photo by Neil Hall/Reuters)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)

A handout picture provided by Solar Impulse on 18 March 2015 shows the Swiss solar-powered plane Solar Impulse 2, HB-SIB, taking off with Swiss explorer Andre Borshberg on board for the third leg Ahmedabad to Varanasi, of the Round-The-World, in Ahmedabad, India, 18 March 2015. Swiss explorers Bertrand Piccard and Andre Borschberg attempt to circumnavigate the world flying with an aircraft, with a 72 metres wingspan, powered only by solar energy without a drop of fuel. (Photo by EPA/Solar Impulse)

“Centuries ago, Inuit hunted the bowhead whale. At that time, whale hunting undoubtedly was part of a complex and very important ritual, if only because of the size of the catch. The position that the ancestors of today's Inuit occupied in the living world involved a relationship with the spirit that inhabited each animal but also their species”. (Photo by Robert Frechette/2014 Sony World Photography Awards)

Przemek Pawlicki performs during training in Leszno, Poland on May 12, 2016. A stunning action-packed catalogue of photographs from sporting events around the world has been released by Red Bull. The energy drink giant's photographers have been busy capturing extraordinary images of action sports and some of the world's greatest daredevils. (Photo by Lukasz Nazdraczew/Red Bull/SWNS.com)