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)

Tech. Sgt. Milo Hinson, 3rd Combat Camera Squadron, uses a flashlight while shooting a Berretta 9mm during the night-fire portion of Advance Weapons, Tactics and Techniques training in San Antonio. During night-fire training, airmen learn how to tactically illuminate targets with flashlights and practice using night vision goggles. (Photo by Staff Sgt. Jonathan Snyder/U.S. Air Force). 2011

Hidden Britain category winner. Garden Spider by Alan Smith from Reading, Berkshire. (Photo by Alan Smith/British Wildlife Photography Awards/PA Wire Press Association)

Pangolins in Crisis: Brent Stirton, South Africa; 1st place, Natural world and wildlife. “Pangolins are the world’s most illegally trafficked mammals, with an estimated one million trafficked to Asia in the last 10 years. Their scales are used in traditional Chinese and Vietnamese medicine, and their meat is sold as a high-priced delicacy. As a result, pangolins are listed as critically endangered and anyone who trades or consumes them is breaking the law. This body of work exposes the trade, while exploring aspects of illegality and celebrating the people who are trying to save these animals”. (Photo by Brent Stirton/Sony World Photography Awards 2020)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

Best portfolio winner. Roseate Spoonbill, Platalea ajaja, by Petr Bambousek, Czech Republic. (Photo by Petr Bambousek/2018 Bird Photographer of the Year)

Marie Lou looks out of the window of gypsy folklore wagon on May 24, 2016 in Staintes Maries de la Mere near Arles, France. Gypsies from all over Europe worship “Sara the Black”, their Saint and patroness, for one week. Sara's statue is situated in the crypt of the church. She wears a multicoloured dress and will carried by the gypsies to the sea at this afternoon. (Photo by Thomas Lohnes/Getty Images)

Collin Williams (front) and Sarah Putnam of Nevada, protesters affiliated with the Occupy Las Vegas movement, participate in a “zombie walk” on the Las Vegas Strip October 30, 2011 in Las Vegas, Nevada. The demonstrators are protesting what they believe is greed and corruption among banking and business leaders in solidarity with other Occupy movements around the world. (Photo by Ethan Miller/Getty Images)