Iron Mountain, an old limestone mine-turned-high-security facility in Pennsylvania, is the unlikely spot where you'll find 150 years of American history packed away in filing cabinets. Millions of photographs, negatives, and even glass plates from 19th Century cameras, are stored in the facility 220 feet underground -- a trove of times gone by. They're the property of Corbis, a company owned by Bill Gates.
Keep clicking to see some of the original images kept there, such as this one of John F. Kennedy and Jacqueline Bouvier. The couple is seen on June 27, 1953, in Hyannis Port, Mass., sitting together in the sunshine at Kennedy's family home a few months before their wedding.