Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)

Blue Man Group founders Phil Stanton, Chris Wink and Matt Goldman pose for a photo at the Blue Man Group's 20th anniversary reunion show to benefit The Blue School at the Astor Theater on April 13, 2011 in New York City.

Children with balloons play beside the statue of British comedy legend Eric Morecambe on January 16, 2012 in Morecambe, England. According to scientists January 16, 2012 was “Blue Monday”, the most depressing day of the year. (Photo by Christopher Furlong/Getty Images)

Photographer of the year second place. “Girl with the Violin”. Location: Colorado, US. Shot on iPhone 13 Pro. United States. (Photo by Kelly Dallas/Courtesy of the artist and IPPAWARDS)

Aerial photography platform SkyPixel received 27,000 entries to its 2016 competition. Here are the winning shots plus some of our favourites. Here: Dam near perfect. Second prize in the same category was of the Huia Dam in Auckland, New Zealand. Hong Kong-based SkyPixel was launched in 2014. (Photo by Brendon Dixon/SkyPixel)

Paddington the Shar Pei dog and his best friend cat named Butler are perhaps the cutest pair you've ever seen. The two of them live with their owner Annie Jacob and three other cats in Tasmania on the south coast of Australia and are pretty much inseparable.

A runner in fancy dress participates in the Virgin London Marathon 2013 on April 21, 2013 in London, England. (Photo by Tom Dulat/Getty Images)

Opposites can attract and Anzac a doe-eyed baby kangaroo has become best friends with Peggy, a tiny squint-eyed wombat. Their unlikely union developed after the pair - both orphans - shared a pouch at the Wildlife Kilmore Rescue Centre in Victoria, Australia. At just over five months old, Anzac was brought to the centre after being rescued in the Macedon Ranges. The joey is in the mother kangaroo's pouch for about eight months, depending on the species, but Anzac was abandoned a few months before he was ready to be free.