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)

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)

Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)

Girls prepare to take part in a mermaid lesson in Rio de Janeiro, Brazil May 28, 2017. Women in Brazil are not unique in their affinity for mermaiding. Classes are held as far away as Texas and some folks wonder if mermaiding will be the next fitness craze. (Photo by Pilar Olivares/Reuters)

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)

People wear traditional Chinese outfits as they walk in Chinatown in Bangkok on February 11, 2021, ahead of the start of the Lunar New Year, which ushers in the Year of the Ox on February 12. (Photo by Lillian Suwanrumpha/AFP Photo)

Hotel staff demonstrates “Lantern Dining Experience”, which enables diners to enjoy meals while protecting themselves against the spread of the coronavirus disease (COVID-19) at Hoshinoya Tokyo in Tokyo, Japan, February 2, 2022. The lantern-shaped transparent partitions are created by Japan’s traditional craftsman and guests staying at the hotel who pay 30,000 yen (about 260 USD) as venue charge can invite others to dine with them under the partitions. (Photo by Kim Kyung-Hoon/Reuters)

Lola, owned by Kate Hansen, of Des Moines, Iowa, waits to be judged at the annual Drake Relays Beautiful Bulldog Contest, Monday, April 25, 2022, in Des Moines, Iowa. The pageant kicks off the Drake Relays festivities at Drake University where a bulldog is the mascot. (Photo by Charlie Neibergall/AP Photo)