A pilot inflates a hot air balloon while taking part in the 38th International Balloon Festival of Chateau-d'oex, Switzerland, 23 January 2016. The festival takes place from 23 to 31 January. (Photo by Vincent Vannay/EPA)

This file photo provided on Sunday February 15, 2015 by the Syrian anti-government activist group Aleppo Media Center (AMC), which has been authenticated based on its contents and other AP reporting, shows Syrian rebels firing locally made shells against the Syrian government forces, in Aleppo, Syria. (Photo by AP Photo/Aleppo Media Center)

The Wildscreen festival is the world’s biggest celebration of screen-based natural history storytelling which takes place every two years in Bristol. Here: “Walrus in Midnight Sun”. Walrus feed mostly on bivalves in productive, shallow and often sandy habitats in the Arctic. This individual, though, arrived on a beach outside Tromsø, northern Norway, and found comfort on a stranded dead sperm whale. After two weeks he approached Audun, and only half a metre away he stretched his tusk forward and touched his hand gently. “This was one of the most memorable moments of my life”, Rikardsen says. He named the 500kg male Buddy. After two months, the dead whale was decomposed and Buddy suddenly disappeared. (Photo by Audun Rikardsen/Wildscreen 2016)

This undated handout photo received from the Antarctic Ocean Alliance on October 28, 2016 shows a adelie penguin jumping onto the ice in the Ross Sea in Antarctica. The world's largest marine reserve aimed at protecting the pristine wilderness of Antarctica will be created after a “momentous” agreement was finally reached on October 28, 2016 with Russia dropping its long-held opposition. (Photo by John Weller/AFP Photo/Antarctic Ocean Alliance)

Passengers hold 500 (bottom) rupee banknotes to buy train tickets at a railway booking counter in Allahabad, India, November 9, 2016. People are queuing up outside banks across India to exchange 500 and 1,000 rupee notes after they were withdrawn as part of anti-corruption measures. Indians will be able to exchange their old notes, which stopped being legal tender at midnight on Tuesday, for new ones at banks until 30 December. The surprise move is part of a government crackdown on corruption and illegal cash holdings. Banks were shut on Wednesday to allow them enough time to stock new notes. There are also limits on cash withdrawals from ATMs. The BBC's Yogita Limaye in Mumbai says there have been chaotic scenes outside many banks. (Photo by Danish Siddiqui/Reuters)

A coach wipes away tears and comforts a girl who was feeling tired during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, May 4, 2016. (Photo by Aly Song/Reuters)

A horse grazes on railway tracks near the old train station on the the Northeast railroad (Ferrovia do Nordeste) in the city of Missao Velha, Ceara state, northeastern Brazil, October 25, 2016. (Photo by Ueslei Marcelino/Reuters)

NEPAL: A devotee is smeared with a vermillion powder while celebrating the “Sindoor Jatra” vermillion powder festival at Thimi, in Bhaktapur, Nepal, April 14, 2016. (Photo by Navesh Chitrakar/Reuters)