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 this facility 220 feet underground -- a trove of times gone by.
The facility, opened for a rare look for CBS News correspondent Whit Johnson, is owned by Corbis, a Bill Gates-owned company that licenses the rights to photographs and visual media.
Some of what Johnson saw there includes famous snapshots and never-before-seen photographs of icons like Marilyn Monroe, Albert Einstein and Abraham Lincoln.
Check out his not-to-be-missed full report in the video below.