An exclusive look behind the locked doors at Levi's HQ's secret archives

To celebrate the fact that our bros at JackThreads are now slinging SF's favorite denim, we were given a special opportunity to rummage around in Levi's HQ's historical archives, and check out everything from crazy artifacts (the oldest jeans in the world, the second weirdest outfit ever worn by Lance Bass, etc.), to letters from famous people, to the weirdest and bestest ads from the past 100 years. Check it out:

Walking into the Levi's archives gives you a real sense of history. And also, the crop top that mannequin is rocking may or may not have been worn by the girl from Destiny's Child who isn't Beyonce or Kelly Rowland. So there's also that.

What you're looking at: the white gloved hand of Levi's badass historian Lynn Downey (so badass, in fact, that she's got an elk-horn-handled Bowie knife hanging from her desk AND she's been on Oprah) opening their roughly eleventy-million-ton safe holding Levi's oldest and most prized artifacts.

Lying within those blankets inside the safe: $500K worth of really, really old things. Plus two SF Giants World Series rings (they had to put them somewhere).

Made in 1879, these are the oldest jeans IN THE WORLD, found in a ghost town in Nevada. Though they are the classic 501s, between 1873 and 1890, they were known as "XX", which was the type of denim they used to make them, sourced from the Amoskeag Millyard in Manchester, NH. Says Lynn, "You touch them, you die."

Boxes on boxes on boxes.

The original people wearing jeans were, for the most part, actual cowboys. But by the 1930s, Levi's started to consciously target coastal city folk who would go to "dude ranches" to play cowboy and likely wear jeans for the very first time. Also, they've come a long way with marketing from calling womenswear "Ladies' Man-Style Shirts".

Oh, this? Just a letter from Cary Grant to Levi's about how he loves the shirts they've sent him. Two things to take away: A) notice he's got his exact address and phone number on his stationery, and he was THE MOST FAMOUS PERSON IN HOLLYWOOD at that time, and B) he says, "I'm not at all sure if I can swagger out in gold-threaded finery." Dude used the term "swagger out" in 1958. Why isn't every major thoroughfare in the country named after Cary Grant?

Those pants you see in front are polished cotton men's pants called "Spikes" released in the late '50s. Internally, they called them "the JellO pants" for obvious reasons. Despite the fact that men nowadays wear brightly colored pants, the Spikes were "NOT a success at the time," according to Downey. They probably should've stuck with classics like these.

In the '60s, Levi's was all about targeting teenagers. And you know how you do that? With DONUT 'N DUNK HOEDOWNS!

You also hire hep bands like Jefferson Airplane to sing a catchy tune, design some trippy art for the vinyl cover, and have your salespeople give it to radio stations.

It's just strange faceless dolls wearing corduroy jackets, okay? Be cool.

In 1974, all the kids were decorating their jeans, so, naturally, Levi's put together a jean-decorating contest. These were from a dude named "Dug" in Georgia.

From the historian: "I don't know what the ad guys were smoking in the '70s when they came up with this idea, but then again... it was the '70s."

And finally, in the '80s, for the Born in the USA album, Springsteen decided to give Levi's a special gift. "We had nothing to do with it; there was no product placement or anything," says Downey. "He wanted to shoot his butt in his own jeans. And he is the Boss, after all."