The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

Focus on two glasses of champagne on floor. Ardent loving couple is sitting on bed and hugging with passion on background. Romantic date concept. (Photo by Olena Yakobchuk/Rex Features/Shutterstock)

The Prince Albert Cairn, built in 1862 by Queen Victoria, is surrounded by snow and ice, near Balmoral, Aberdeenshire, Scotland, Friday November 22, 2024. (Photo by Jane Barlow/PA Wire via AP Photo)

A breeder poses with fruits and specially made high-fibre bread, for 36-year-old giant panda Jia Jia, at the Hong Kong Ocean Park, China June 30, 2015. Jia Jia, the oldest giant panda living in captivity, is set to challenge the world record for the animals' longevity, with her age said to put her on par with a human centenarian. (Photo by Tyrone Siu/Reuters)

Sabera Bayanne, 20, a student of the Shaolin Wushu club, practices in Kabul, Afghanistan January 29, 2017. On a snowy mountaintop to the west of Kabul, a group of Afghan girls practise the flowing movements of Wushu, a sport developed from ancient Chinese kung fu martial arts, stretching and bending and slashing the air with bright swords. (Photo by Mohammad Ismail/Reuters)

A Thorneycroft motor van as used during World War I. (Photo by Topical Press Agency/Getty Images). August 1914

School children take photographs as Queen Elizabeth II arrives in Valentine's Park Redbridge as part of her Diamond Jubilee tour of the UK on March 29, 2012 in London, England. (Photo by Chris Jackson/Getty Images)

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)