Men selling sheep wait for customers at a local livestock market, ahead of the Eid al-Adha festival, in Lagos, Nigeria September 11, 2016. (Photo by Akintunde Akinleye/Reuters)

Al Fursan, the UAE Air Force aerobatic display team, perform during the opening of the Dubai Airshow in United Arab Emirates, Sunday, November 8, 2015. Dubai Airshow took off today to a slow start amid little expectations of major orders to match the multi-billion-dollar sales generated at the last edition of the biennial fair. (Photo by Kamran Jebreili/AP Photo)

A girl carries bottles of water filled from a charity tank at a camp for internally displaced people (IDPs) near Sanaa, Yemen on March 25, 2022. (Photo by Khaled Abdullah/Reuters)

A cat looks on near the Victory Pillar at the ruins of the Serapeum of Alexandria, an ancient Greek temple dating to the Ptolemaic and Roman periods (246 BC – 391 AD) dedicated to the city's protector deity Serapis, in Egypt's northern coastal city of Alexandria on November 24, 2023. The giant Corinthian column, commonly misidentified as “Pompey's Pillar”, is a Roman triumphal column set up in honour of the Roman emperor Diocletian (298–302 AD), and originally supported a colossal porphyry statue of the emperor in armour. (Photo by Amir Makar/AFP Photo)

Muqtada Haider turns the switches to transfer electricity to private homes in Baghdad, Iraq, Friday, September 10, 2021. In Iraq, electricity is a potent symbol of endemic corruption, rooted in the country’s sectarian power-sharing system. This contributes to chronic electrical outages of up to 14 hours a day in a major oil-producing nation with plentiful energy resources. (Photo by Hadi Mizban/AP Photo)

A Yemeni pro-government fighter is pictured during fighting with Huthi rebels on the south frontline of Marib, the last remaining government stronghold in northern Yemen, on November 10, 2021. A Yemeni military official said that 28 fighters from the pro-government Obaida tribe and seven government forces were killed in clashes with rebels south of Marib over the previous 24 hours. (Photo by AFP Photo/Stringer)

In this handout photograph received from Sumukha J.N on December 15, 2016, the newly-discovered spider Eriovixia Gryffindori sits on a leaf in the Kans in India's Western Ghats. (Photo by Sumukha J.N./AFP Photo)

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)