Polar bears prepare to feast on the remains of a bowhead whale, harvested legally by whalers during their annual subsistence hunt, just outside the Inupiat village of Kaktovik, Alaska, USA, 10 September 2017. As climate change shrinks their natural habitat, polar bears are turning Kaktovik into their very own sanctuary city. (Photo by Jim Lo Scalzo/EPA/EFE)

A jaguar ambushes a giant jacare caiman high up on the Three Brothers River in the Pantanal in Mato Grosso, Brazil. The cat wrestled with the reptile for over twenty minutes in a death struggle witnessed by photographer Chris Brunskill just after ten o'clock in the morning on the 26th of September, 2017. Caimans form a large part of the jaguar's diet in the Pantanal but battles such as this are very rarely observed and seldom photographed. (Photo by Chris Brunskill Ltd/Getty Images)

These frozen caves seem almost otherworldly as they daylight illuminates them. Matej Kriz’s shots reveal the beauty of the brilliant caves, but he’s also very aware of how deadly they can be. The photographer captured the amazing shots in the Vatnajokull National Park on the Breidamerkurjokull glacier tongue. Here: The ice caves, taken in the Vatnajokull National Park in Iceland, on November 11, 2017. (Photo by Matej Kriz/Caters News Agency)

The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

X Factor and Celebrity Big Brother starlet Chloe Khan is seen working up a sweat at her luxury home on August 30, 2016. The CBB star squeezed into a pair of super-tight leggings and a teeny crop top for a very public workout. She may be a self-made millionaire, but life wasn't always so good for Chloe Khan. The Celebrity Big Brother star, 25, has revealed she was brought up in poverty as a child in Wakefield, West Yorkshire, UK. Chloe lived with her mother on a council estate before she auditioned for the X Factor and became a playboy model. (Photo by Palace Lee)

An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)

These goats threw caution to the wind and scaled this Argan tree right to the very top, even balancing on the most unsturdy of branches. It looks like a bit of a baa-lancing act, but the goats hooves are perfectly adapted to climbing the trees, where they graze on the Argan fruit. Amateur photographer Burak Senbak, 51, took these photos whilst travelling through Morocco in July 2016. Burak is originally from Turkey and works as a mechanical engineer, but has pursued his passion for photography for 10 years. Intrigued by the sight of goats in a tree, Burak couldnt resist the opportunity to take some photos, and said the goats proved a perfect subject. (Photo by Burak Senbak/Caters News)

Under Exposed: Pekka Tuuri (Finland) – Great white shark, Isla Guadalupe, Mexico. “Isla Guadalupe is the world capital when it comes to observing great white sharks, but cage diving seriously limits the possibilities to take ‘fresh’ pictures. When I took this, the water close to the surface was quite milky, making photography very challenging. From out of the “mist”, I saw this great white shark lurking behind a school of fusiliers. I quickly focused on the shark and set a wide aperture to get focus blur on the fish, along with a fast shutter to avoid excessive motion blur”. (Photo by Pekka Tuuri/The Outdoor Photographer of the Year/The Guardian)