Riot police clash with protesters during a rally to demand a referendum to remove Venezuela's President Nicolas Maduro in Caracas, Venezuela, September 1, 2016. (Photo by Marco Bello/Reuters)

A protester gestures during a “Yellow vest” protest against higher fuel prices during clashes on the Champs-Elysees in Paris, France, November 24, 2018. (Photo by Benoit Tessier/Reuters)

Police intervene as two women fight at a pro-law enforcement rally that clashed with counter protesters demonstrating against racial inequality, in Denver, Colorado, U.S. July 19, 2020. (Photo by Kevin Mohatt/Reuters)

A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

Demonstrators help a fellow protester during clashes with security forces during an opposition rally in Caracas, Venezuela on April 4, 2017. Protesters clashed with police in Venezuela Tuesday as the opposition mobilized against moves to tighten President Nicolas Maduro' s grip on power. Protesters hurled stones at riot police who fired tear gas as they blocked the demonstrators from advancing through central Caracas, where pro- government activists were also planning to march. (Photo by Carlos Garcia Rawlins/Reuters)

A Palestinian protester uses a sling to hurl stones towards Israeli troops during clashes near the Jewish settlement of Bet El, near the occupied West Bank city of Ramallah October 5, 2015. Violence intensified in Jerusalem and the West Bank on Sunday after Israelis were targeted in two stabbing attacks and a Palestinian was killed in a clash with Israeli troops, officials said. (Photo by Mohamad Torokman/Reuters)

A man carrying an axe walks past a house marked with bullet holes in Gyallesu district after recent clashes between Shi'ites and the army in Zaria, Kaduna state, Nigeria, February 3, 2016. Sectarian tensions are rising in Nigeria's Muslim north, where hundreds of Shi'ites were killed in clashes with the army in the town of Zaria in December, according to Shi'ites and rights groups. Following the clashes, bulldozers sent by the state levelled Shi'ite shrines, a cemetery and offices in the deeply divided town. The region is already grappling with an insurgency waged by the jihadist Boko Haram group. (Photo by Afolabi Sotunde/Reuters)

A Palestinian protester, dressed as Santa Claus, reacts after inhaling tear gas fired by Israeli troops during clashes in the West Bank city of Bethlehem December 23, 2016. (Photo by Mussa Qawasma/Reuters)