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)

A man carries an injured woman in a site hit by what activists said were airstrikes carried out by the Russian air force in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria January 9, 2016. At least 70 people died in what activists said where four vacuum bombs dropped by the Russian air force in the town of Maaret al-Numan; other air strikes where also carried out in the towns of Saraqib, Khan Sheikhoun and Maar Dabseh, in Idlib. (Photo by Khalil Ashawi/Reuters)

Bulls fight during the Maghesangranti festival at Talukachandani village in Nuwakot district near Kathmandu, Nepal January 15, 2016. The village organizes the bullfight during the Maghesangranti festival that commemorates the start of the holy month of Magh, ushering in the coming of warmer weather and longer days. (Photo by Navesh Chitrakar/Reuters)

A Palestinian throws snow at his wife during a snow storm in West Bank old city of Hebron, January 26, 2016. (Photo by Mussa Qawasma/Reuters)

A cat and a seagull feeding on a street in Heybeliada, the second largest of the Prince Islands in the Sea of Marmara, near Istanbul, Turkey on February 01, 2017. (Photo by Sebnem Coskun/Anadolu Agency/Getty Images)

Planned improvements to Rio’s favelas have meant increases in rent, forcing the poorest families into squatting in unoccupied buildings. Photographer Tariq Zaidi visits the Mangueira community favela, less than 1km from the showpiece Maracanã stadium, to see what life is like for the women living there. Here: Victoria, 12, at her home in Mangueira. (Photo by Tariq Zaidi/The Guardian)

The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

Hikers walk to reach the top of Naqba Rum area in South Sinai, Egypt, November 20, 2015. Bedouins in the "Sinai is Safe" group guided more than 100 hikers over a 25 km (15 mile) trek over the trails of the White Canyon and the Closed Canyon. The NGO aims to challenge mainstream perceptions of the area by encouraging Nile Valley residents to explore the untamed wilderness with the Bedouin tribes. (Photo by Asmaa Waguih/Reuters)