In this May 12, 2017 photo, Pupy, an African elephant, stands in the doorway of his enclosure at the former city zoo now known as Eco Parque in Buenos Aires, Argentina. A year ago the 140-year old Buenos Aires zoo closed its doors and was transformed into a park. The first director decided that the animals should be housed in buildings that reflected their countries of origin. A replica of a Hindu temple was built for the Asian elephants. (Photo by Natacha Pisarenko/AP Photo)

A Humboldt penguin stands on weighing scales whilst being photographed by members of the press during a photocall at the annual weigh-in at London Zoo in London, Britain, 24 August 2016. Every animal that is in the zoo is weighed and measured and the statistics recorded so the data can be shared with zoos across the world. (Photo by Hannah McKay/EPA)

Vitali Klitschko of Ukraine poses in front of Odlanier Solis of Cuba during the weigh in at Sport Karstadt on March 18, 2011 in Cologne, Germany. The WBC World Championship Heavyweight fight between Vitali Klitschko of Ukraine and Odlanier Solis of Cuba will be held on 19 March 2011.

Jo-Anne McArthur’s book of photographs puts the spotlight on ethics of zoos around the world. Accompanied by essays by Born Free Foundation’s Virginia McKenna and philosopher Lori Gruen, the images and stories are also shared online through “A Year of Captivity”. Here: Asian Elephant, Denmark, 2016. (Photo by Jo-Anne McArthur/Born Free Foundation/The Guardian)

A daredevil photographer is determined to capture London in a whole new light – by scaling the city’s many rooftops. Jacob Riglin, from Richmond Upon Thames, photographs the nation's capital from above – hanging from scaffolding, dangling his legs over the edge of buildings and looking down from perilous heights. Such images have gained the photographer, 20, an incredible fan base on Instagram, which has seen his follower count rise to more than 150,000. He said, “I had always been interested climbing and getting that adrenaline rush from feeling on top of the world”. Here: Jacob looking out to the London skyline. (Photo by Jacob Riglin/Caters News)

A zoo worker feeds milk to tiger cubs born on the first day of the Lunar New Year and Year of the Rooster at Sriracha Tiger Zoo in Chonburi province, Thailand, January 30, 2017. (Photo by Athit Perawongmetha/Reuters)

Two holidaymakers amuse themselves with a porter's trolley whilst waiting for their train at Euston Station, London, 5th August 1939. (Photo by A. J. O'Brien/Fox Photos/Getty Images)

A West African Slender-snouted Crocodile is pictured in its enclosure at the zoo of Abidjan, Ivory Coast September 9, 2016. (Photo by Luc Gnago/Reuters)