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)

A worker wearing a protective mask uses a blower to remove leafs from a walkway during sunny autumn weather near Stallikon, Switzerland on October 27, 2020. (Photo by Arnd Wiegmann/Reuters)

Fluffy toy panda bears as part of the art installation “Panda mie” by Italian restaurant owner Giuseppe “Pino” Fichera sit over beers at his restaurant “Pino's” to raise awareness of the COVID-19 lockdown's business impact on gastronomy in Frankfurt, Germany, November 24, 2020. (Photo by Kai Pfaffenbach/Reuters)

A reflection on waste liquid shows a tourist walking near the Blue mosque at the Sultanahmet Square on the first day of the Muslim fasting month of Ramadan in Istanbul on April 13, 2021. (Photo by Ozan Kose/AFP Photo)

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)

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

A Ukrainian service member smokes near a frontline, amid Russia's attack on Ukraine, in Donetsk region, Ukraine on February 8, 2023. (Photo by Yevhenii Zavhorodnii/Reuters)

Lucy Blacker from Australia takes to the water at the 40 Foot for a Christmas Day Swim in Ireland on December 25, 2022. (Photo by Alan Betson/The Irish Times)