A reporter stands outside the front door of a house registered to a trading company operated by Navinder Singh Sarao in Hounslow, west of London. on April 22, 2015. Sarao was arrested in connection with the Wall Street flash crash of 2010. Adrian Dennis/AFP/Getty Images hide caption

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Fake medicines are a 21st-century scourge, but they've been around for a long time. This advertising trade card for snake oil was printed in New York City around 1880. Transcendental Graphics/Getty Images hide caption

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Two years after the collapse of the factory at Rana Plaza, families of victims gather, holding photos of their lost loved ones. Amy Yee for NPR hide caption

itoggle caption Amy Yee for NPR

"Why does everyone have to be here at the same time? Why do we need to know how many hours a week people work?" — Ricardo Semler James Duncan Davidson/TED hide caption

itoggle caption James Duncan Davidson/TED

As the Apple Watch goes on sale Friday, it's unclear if the gadget and others like it can attain the utility and prominence smartphones have in the past eight years. Ryan Emberley/AP hide caption

itoggle caption Ryan Emberley/AP