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)

Wakodahatchee wetlands, Delray Beach, Florida, US. Equipped with sinewy necks and spear-like bills, great blue herons can lunge with fearsome speed to strike their aquatic prey. Adults will also employ rapid stabbing motions as one aspect of their complex courtship displays; they’re seemingly dangerous moves, but fitting to the intensity of mating season. (Photo by Melissa Rowell/Audubon Photography Awards)

A baby bush-baby in a set of scales at London Zoo shortly after birth. (Photo by Fox Photos/Getty Images). 10th August 1938

A meteorite burns up in the atmosphere as seen in this photo taken near of Salgotarjan, 109 kms northeast of Budapest, Hungary, late 21 April 2015. The Moon and Venus can be seen on the left. (Photo by Peter Komka/EPA)

Burlesque dancer INGA performs during the Viva Las Vegas Rockabilly Weekend's Burlesque Showcase hosted by John Waters at the Orleans Arena on April 19, 2019 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

The music group, Boyfriend, performs at the Gentilly Stage at the New Orleans Jazz & Heritage Festival in New Orleans, Thursday, April 25, 2019. (Photo by Doug Parker/AP Photo}

A man passes by a wall with graffiti in Beirut, Lebanon, on May 29, 2019. (Photo by Bilal Jawich/Xinhua News Agency/Alamy Live News)

A stroller walks his dogs in an autumnally colored forest in Cuxhaven, nothern Germany on November 7, 2018. (Photo by Patrik Stollarz/AFP Photo)