This is the amazing moment a heroic hippo saved a gnu from certain death. After being bitten by a crocodile, the large antelope is seen being dragged slowly under the water. But in a miraculous turn of events, a nearby hippo is seen making its way across the water to help the animal in its hour of need. Photo: One of the biggest hippos protects the gnu as it makes its way back to the shoreline, guarding it from any further attacks. (Photo by Vadim Onishchenko/Caters News)

An Iraqi woman attends a festival commemorating the International Day of Peace in Baghdad, September 21, 2015. (Photo by Thaier al-Sudani/Reuters)

“This cheeky polar bear tried to hitch a lift off an unsuspecting driver by clambering into the back of his pick-up truck. The curious creature spent about half an hour inspecting the vehicle and its owner before casually trying to climb aboard. However, the truck must not have been up to scratch because the 7ft bear, weighing approximately 300lbs, promptly jumped back out and sauntered off”. – Barcroft Media. Photo: “Awright mate, any chance of a lift to the North Pole?” (Photo by Steven Kazlowski/Barcroft Media)

Passengers pose for a selfie as they wait for the Night Tube train service at Oxford Circus on the London underground system in London, Britain August 20, 2016. The London Underground is starting its first-ever overnight service, a move city leaders hope will make the British capital a truly 24-hour city and bolster the local economy. (Photo by Paul Hackett/Reuters)

Tattoo artist Tokyo Hiro draws a scorpion to be tattooed on a customer at the Tattoo the Earth Festival August 9, 2002 in Oakland, California. The Tattoo the Earth festival focuses on the tattooing culture and is the largest tattoo event of its kind. (Photo by Justin Sullivan/Getty Images)

A photographer has captured these eerie images showing the scale of some of Britain's deepest darkest wonders. Mike Deere, from Reading, heads to daunting locations such as abandoned mine shafts, miles of sewer tunnels that snake underneath London and even disused cooling towers. Photo: This incredible picture was taken at the Box Freestone Mine, in Wiltshire. Mike revealed that even experienced map readers would struggle to navigate their way around the seemingly endless tunnels that he and his friends visit. (Photo by Mike Deere/Caters News)

A participant has his body painted before a regional bodybuilding championship in Stavropol, southern Russia, April 10, 2016. (Photo by Eduard Korniyenko/Reuters)