Riot police face off with demonstrators at the “Occupy Denver” camp on October 29, 2011 in Denver, Colorado. Following a march by protesters, police moved in on their encampment to tear down recently erected tents. They arrested numerous protesters, pepper-sprayed others and others reportedly fired rubber bullets at the crowd during the confrontation. (Photo by John Moore/Getty Images)

A muslim woman protests opposite Downing street against the military action taken by the UK, USA and France against Libya on March 21, 2011 in London, England. The Pentagon says that United States and United Kingdom military forces have fired more than 110 missiles, with French planes attacking pro-Gaddafi forces near rebel-held Benghazi. (Photo by Oli Scarff/Getty Images)

Bavarian farmers load their cows on a boat before they drive over the picturesque Lake Koenigssee, Germany, October 3, 2015. Before the winter season approaches the farmers have to drive their cattle down from their Alpine meadows to a narrow valley that can only be reached by boat. (Photo by Michael Dalder/Reuters)

These photographs of hundreds of ducks following their leader down a river are truly mesmerizing. Rafeur Rahman of Bangladesh climbed a high bridge and saw hundreds of ducks apparently playing a game of follow the leader. More than 500 ducks live on the river, where the mosses and snails provide the perfect habitat. Here: Ducks in the river Baral in Bangladesh. (Photo by Rafeur Rahman/Caters News Agency)

Shortlisted images in the running to be crowned Photobox Instagram photograph of the year range from furry friends to the Holi festival to the meaning of love. Judges, including the Guardian’s former picture editor Eamonn McCabe, have whittled down 180,000 submissions to unearth a shortlist that celebrates the best of social media. Winners will be announced October 3, 2018. Here: Najac, France. Travel shortlist. (Photo by Aaron Jenkin/@aaronjenkin)

Soldiers from 12 Mechanized Brigade perform a simulated casualty evacuation at the Ministry of Defence training area at Copehill Down on Salisbury Plain on March 9, 2012 in Wiltshire, England. The Defence Secretary Philip Hammond visited the military facility to meet soldiers from the Brigade who are shortly to deploy to Afghanistan for Operation Herrick 16, and troops from the 3rd Battalion, the Yorkshire regiment which lost five of the six men who died this week in the deadliest single attack in Afghanistan since 2001. (Photo by Matt Cardy/Getty Images)

A government awareness poster for wearing surgical masks is seen reflected and upside-down in the Dambovita river in Bucharest, Romania, 19 November 2020. The poster, depicting a man wearing a surgical mask, reads: “I WEAR A MASK BECAUSE I KNOW THAT ONLY TOGETHER WE WILL SUCCEED!”. As the number of COVID-19 infections increased, authorities decided that wearing a protective mask should become mandatory at all times in all public places. (Photo by Robert Ghement/EPA/EFE)

The 139-year-old Victorian house known as the Englander House is hoisted on a flat bed and pulled down Franklin Street towards its new location six blocks away, as the original site is to be used to build a 48-unit, eight-story apartment building, in San Francisco, California, U.S. February 21, 2021. (Photo by Brittany Hosea-Small/Reuters)