Fans of the Tampa Bay Rays celebrate during the singing of "God Bless America" during the game against the Boston Red Sox at Tropicana Field on Sept. 11 in St. Petersburg, Fla. J. Meric/Getty Images hide caption

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In virtually every county, there is a Walmart open every hour of every day, and every one of those Walmarts is being visited by 37,000 people a week — that's 220 people an hour, in every Walmart, every hour of the day. Here, a Walmart worker pulls carts at a store in Pittsburg, Calif. Paul Sakuma/AP hide caption

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An Amtrak Police K-9 watches while commuters depart for rush hour during "Operation Railsafe" at Union Station in Washington, D.C., last October. Brendan Smialowski/Getty Images hide caption

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One of the earliest accounts of a surprise attack comes from Greek mythology: the Trojan Horse. Rischgitz/Hulton Archive/Getty Images hide caption

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In the East, they'll sell you the Brooklyn Bridge. In the West, it's the Golden Gate. Saul Loeb and Gabriel Bouys/AFP/Getty Images hide caption

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A vintage illustration of Wall Street, 1908 Library of Congress/Prints and Photographs Division hide caption

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President Obama walks back to the Oval Office after speaking in Rose Garden of the White House on Tuesday, after the Senate passed the debt ceiling legislation. Carolyn Kaster/AP hide caption

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