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)

Heimana Reynolds of USA in action during a training session prior to the World Skate Park World Championships at the Parque Candido Portin​ari in Sao Paulo, Brazil, 11 September 2019. (Photo by Sebastião Moreira/EPA/EFE)

English radio and television presenter Caroline Flack, 40, seen arriving at Bagatelle restaurant in Mayfair on November 08, 2019 in London, England. (Photo by GORC/GC Images)

Ray Yang, a celebrity trainer, takes a selfie before the start of a workout session during TV program "The Body Show" at a gym in Seoul, September 19, 2015. Looks no longer centre only on the face in beauty-obsessed South Korea, where more women are hitting the gym to improve muscle tone and physical health. As the ideal of beauty evolves in a country that is a trendsetter in cosmetics and the pursuit of plastic surgery, women's fitness has become a growth business, say purveyors of health products, from diet supplements to dumb-bells. (Photo by Kim Hong-Ji/Reuters)

A Sotheby's employee poses with a “Return of the Jedi” promotional C-3PO Helmet 1983, estimated at £15,000-£25,000 created by George Lucas' visual effects company during a photocall at Sotheby's in London, Britain on December 6, 2019. (Photo by Thomas Mukoya/Reuters)

German President Frank-Walter Steinmeier struggles with his glasses and face mask as he attends a press conference after visiting the Salzburg Festival in Salzburg, Austria, Saturday, August 22, 2020. (Photo by Kerstin Joensson/AP Photo)

A worker wearing a protective mask uses a blower to remove leafs from a walkway during sunny autumn weather near Stallikon, Switzerland on October 27, 2020. (Photo by Arnd Wiegmann/Reuters)

(L-R) Canadian actor Patrick J. Adams as Michael Ross and American member of the British royal family and a former actress Meghan Markle as Rachel Zane at “Breakfast, Lunch and Dinner”, Episode 402 in April 2014. (Photo by Ian Watson/USA Network/NBCU Photo Bank/NBCUniversal via Getty Images)