A photographer could bear-ly believe his eyes when a bear started waving at him. The friendly animal wandered to the front of his enclosure before sitting back in full view of zoo guests. He then lifts his powerful paw and excitedly waves in an almost human-like way at his new audience. The hilarious encounter was captured by keen photographer Andrey Slepnev, 31, while on a trip to Madrid Zoo, Spain on March 24, 2016. (Photo by Andrey Slepnev/Caters News)

While most people head for cover at the first sign of a storm, this man runs straight toward it. Storm chaser and father of three Mike Olbinski is addicted to photographing extreme weather and regularly takes on tornadoes and supercell thunderstorms in a bid to capture extraordinary images. The photographer, from Phoenix, often travels hundreds of miles a day to reach the eye of a storm. He first became hooked on the unusual hobby almost a decade ago, following the birth of his daughter. Here: A stunning monsoon sunset coupled with intense lightning creating an amazing scene on August 26, 2017. (Photo by Mike Olbinski/Caters News Agency)

This perfectly-timed GoPro snap captures the moment an angrymagpiecame within inches of a biker, as swooping season takes hold in Australia. The notoriously aggressive bird can be seen flying with its wings tucked in so it looks exactly like a torpedo in the magnificent photograph from Middlemount, Queensland. Retail businesswoman Monique Newton, 53 was riding pillion with a friend when she spied the divebombing bird – but rather than speed off, they slowed down to capture it up close. (Photo by Monique Newton/Caters News Agency)

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)

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)