Windsor Castle, home to the British monarchy for hundreds of years, was built by William the Conqueror in the 1070s, according to the monarchy's official website. W. Buss/De Agostini/Getty Images hide caption

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It's a drone delivery! This copter is ferrying medicine from a pharmacy to the headquarters of Deutsche Post in Bonn, Germany, part of a test of drone capabilities. Andreas Rentz/Getty Images hide caption

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Parts of the subway system were shut down in the city of Bursa when a major power outage hit cities and provinces across Turkey on Tuesday. Anadolu Agency / Getty Images hide caption

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A police officer is silhouetted through the emergency room door at a public hospital in San Pedro Sula, Honduras. With 91 murders per 100,000 people, the Central American nation is often called the most violent in the world. The homicide rate is roughly 20 times that of the U.S. rate, according to a 2011 U.N. report. Esteban Felix/AP hide caption

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