It's the end of the workday in Charlotte, and a crowd of bankers and business people are heading home for the day, striding down a plain, ordinary sidewalk next to a nondescript brown building on Trade Street.

What these business people perhaps don't know is that just below their feet, about a story or two down, is a bustling underground operation and a steel-encased vault containing billions of dollars in cash.

That brown building is the Federal Reserve - one of 28 branches around the country. And if you're thinking about pulling off a heist a la Gerard Butler, think again. Charlotte's branch of the Federal Reserve is one of the most highly-secure buildings in the city, with cameras, motion detectors, security guards, and high grade locks at nearly every turn.

The vault itself is the most tightly-secured area. It's roughly three stories high and two basketball courts wide, with a door made of steel as thick as a person. Generally, humans are not allowed to step foot inside.

But on this week's FAQ City, we'll get a rare peek alongside WFAE listener Cailen Sniker, an engineer from Huntersville who wrote in the prompt for our episode ("Are there any cool underground spots in Charlotte, and what are they like inside?")

Special thanks to Kelly Stewart, our tour guide for this episode, as well as the rest of of the staff at the Charlotte branch of the Federal Reserve.

If you'd like to see the underground in person, the Fed offers public tours Tuesday through Thursday for school field trips and adult groups. More information here: https://www.richmondfed.org/about_us/visit_us.

Also, we're looking for more listener questions to investigate for upcoming episodes. Tell us what you're curious about! Submit your question in the box below, and we may be touch.

While you're at it, make sure to subscribe and rate/review the podcast on Apple Podcasts, NPR One, and Google Play.

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