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)

Players in action during the Swamp Soccer Championships 2019 in Hyrynsalmi, Finland, 19 July 2019. The World Championship in swamp football is played annually on Vuorisuo bog in Hyrynsalmi. (Photo by Tomi Hanninen/EPA/EFE)

A visitor is dwared between the wheels of BelAZ 450-ton dump truck (L) and BelAZ 360-ton dump truck (R) at the plant of Belarusian manufacturer of heavy trucks and equipment for earthmoving, BelAZ, in Zhodino, some 55 km from Minsk, Belarus, 27 August 2019. The company mostly delivers its products to CIS mining companies, mainly from Russia and Ukraine. (Photo by Tatyana Zenkovich/EPA/EFE/Rex Features/Shutterstock)

A fan of England cheers prior to the UEFA EURO 2020 quarter final match between Ukraine and England in Rome, Italy, 03 July 2021. (Photo by Mike Hewitt /EPA/EFE)

Icelandic horses play in their paddock at a stud farm in Wehrheim near Frankfurt, Germany, as a mist rolls in on Thursday, August 5, 2021. (Photo by Michael Probst/AP Photo)

A diver in a pool at the Army 2021 International Military and Technical Forum, at the Patriot military park in Moscow Region, Russia on August 22, 2021. (Photo by Sergei Karpukhin/TASS/Alamy Live News)

The sun rises through the thick fog that covers the city of Frankfurt, Germany, Friday, November 12, 2021. (Photo by Michael Probst/AP Photo)