These images show the unique bond a group of free divers formed with gigantic sperm whales. Swimming just inches away from the huge mammals, the divers are dwarfed in size, made to look like specks in comparison. The photos were taken by renowned underwater photographers Alexandre Roubaud and Alexandre Voyer, who are based in Paris but travel the world to capture such stunning imagery. Here: a diver with a sperm whales. (Photo by Alexandre Roubaud/Alexandre Voyer/Caters News)

Members of the New People's Army (NPA) female guerrillas perform a cultural show during the release of a Philippines army soldier in Sugbongcogon town, Misamis Oriental, southern Philippines, November 20, 2015. NPA spokesperson Allan Juanito warned that they will seize more soldiers to exchange them with the government as "Prisoners of war". (Photo by Froilan Gallardo/Reuters)

A photographer is using a unique method to show the shift from day to night across famous cities in spectacular images. Daniel Marker-Moors' take on time-lapse photography – which he calls time slice – sees the photographer snap image after image, before combining them to create beautiful, vibrant works. His images usually focus on a point in the day with the most dramatic change in light, such as sunrise or sunset. Marker-Moors, from Los Angeles, begins by shooting hundreds and sometimes thousands of images from the same spot. Here: Chicago – 35 photographs, 15 minutes. (Photo by Daniel Marker-Moors/Caters News)

Neil Zeller's snaps were taken across Canada, where he photographs the northern lights dancing across a dark night sky. In one stunning shot, Zeller, 42, even manages to capture a flash of lightning beneath a storm cell while an aurora gives off a magnificent green glow. The photographer, from Calgary, Alberta, describes himself as a night person, and became interested in night photography about 10 years ago. (Photo by Neil Zeller/Caters News)

Dont get catty. These roar-some images show the moment two female tigers came to blows in a bitter dispute over territory. Rarely ever seen in the wild let alone on camera, the dramatic images show a white Siberian tiger and orange-coloured tiger slashing ferociously at each others face and eyes. The intense altercation erupted into violence when the smallest of the pair, the orange striped tiger known as Shadow, attempted to expand its hunting ground. But white tiger, TiBo, wasnt willing to give up the ground without a fight and was forced to use its size and weight to put Shadow firmly back in her place. (Photo by Alex Kirichko/Caters News/SIPA Press)

This is the hilarious moment a terrified baby hippo ran screaming for its mum when a flock of bird landed on its back in South Luangwa National Park in Zambia. The hippo was seen screaming, running and twisting from side to side in a desperate bid to shake off the red and yellow ox-pecker birds. Ox-peckers and hippos usually have a mutually beneficial relationship where the birds help free hippos of ticks and other parasites by feeding on them. (Photo by Marc Mol/Caters News/SIPA Press)

A man salts a downtown sidewalk in Washington, Thursday, March 5, 2015, as snow begins to fall. The U.S. federal government said its offices in the Washington area will be closed Thursday because of a new round of winter weather expected in the region. The Office of Personnel Management said non-emergency personnel in and around Washington were granted excused absences for the day. Emergency employees and telework-ready employees were expected to work. (AP Photo/Andrew Harnik)

A canine-crazy photographer helped make his dog healthy after seeing him raid the fridge by posing him up with fruit. Scott Cromwell, 43, from Oklahoma City, caught faithful mutt Winston guzzling hot dogs after he looted the refrigerator. Well-trained Winston was then happy to get his five-a-day by taking tongue-in-cheek snaps with red apples, bananas, grapes, limes and orange. (Photo by Scott Cromwell/Caters News)