A nurse adjusts the position of a patient's arm during dialysis treatment. The treatment requires trained staff that weren't readily available in the aftermath of Hurricane Sandy. Michael Donne/Science Source hide caption

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Photographer David Blackwell and his wife prepared for the apocalypse. Cats and cat food? Check. Toilet paper? Check. Exploding volcanoes and hurtling asteroids? Not so much. David Blackwell/Flickr hide caption

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People check their smartphones while standing in the street shortly after an earthquake struck Washington on Tuesday. Mandel Ngan/AFP/Getty Images hide caption

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