Smithsonian treasures revealed: Take a rare tour of world's largest museum and research complex

Every year, 30 million people visit the Smithsonian, but few get an insider's look at the world's largest museum and research complex. But recently, CBS News did.

Curator Harry Rubenstein shared a tour of the museum's amassed objects, from dinosaur bones to spacecraft -- most of which remain stashed away, out of the public's view.

"In part, we want to preserve this material for future generations. There's nothing like seeing the real object," Rubenstein said of the collection.

You can check out some of those objects -- from a political banner from the inauguration of 1801 to a gold pocket watch carried by Abraham Lincoln -- with CBS News' Bill Plante in the video above.

So how do they get all of this stuff? Plante explained on "CBS This Morning" that the Smithsonian sends its curators out to political campaigns, conventions, and to demonstrations of all kinds, where they ask people if they'd be willing to donate things. The Smithsonian is also the beneficiary of people who are offering up their own items, some of which is just stuff, but occasionally, a treasure is found.