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 horse pulls a driving school car as other drivers push their vehicles behind during a demonstration by driving instructors in Belgrade, September 25, 1992. Due to gasoline shortage in the Yugoslav capital, driving instructors are staying away from work. (Photo by AP Photo)

Nepalese devotee women take a holy bath after offering prayers in Pashupathinath Temple premise during the month-long Swasthani Bratakatha festival, devoted to goddess Shree Swasthani in Kathmandu on February 8, 2016. Devotees recite Holy Scripture and women pray for wellbeing of their spouses throughout the month-long fast. (Photo by Skanda Gautam via ZUMA Wire)

Visitors visit the upside-down family size house in Taipei, Taiwan, 23 February 2016. The three story upside-down family size house attracts hundreds of visitor’s who are amused with the exhibit. According to the organizers, the total cost of the construction is around 600,000 US Dollars and took 2 months to complete. (Photo by Ritchie B. Tongo/EPA)

A fishing boat (L) heads out to sea at dawn in Lhokseumawe, Aceh on August 9, 2021. (Photo by Azwar Ipank/AFP Photo)

Decaying fishing trawlers known collectively as The Fleetwood Wrecks, are seen at low tide on the banks of the River Wyre in Fleetwood, Britain on September 26, 2023. (Photo by Lee Smith/Reuters)

A workman takes a siesta on a girder during the building of Radio City, the city of New York spread out below. (Photo by General Photographic Agency/Getty Images). Circa 1933