The Langley, Virginia, Starbucks is one of the busiest in the world.

Located inside the CIA compound, it is also the most secretive, writes Emily Wax-Thibodeaux at The Washington Post.

Here are a few ways the so-called "Stealthy Starbucks" protects the identities of its CIA patrons.

1. Baristas don't write any names on the drinks.

"Giving any name at all was making people — you know, the undercover agents — feel very uncomfortable. It just didn’t work for this location," an anonymous worker told Wax-Thibodeaux.

2. Workers are put through an intense background check process.

The address for the CIA Starbucks doesn't even show up on a GPS, one worker told the WashPo. Once workers get the job, they aren't allowed to reveal where they work.

"The most I can say to friends is that I work in a federal building," one barista said.

The Starbucks is located deep inside the CIA's headquarters. Google Earth

3. There are no rewards cards.

"Officials fear the data stored on the cards could be mined by marketers and fall into the wrong hands, outing secret agents," writes Wax-Thibodeux.

Despite the complicated logistics of running the CIA Starbucks, managers say that the coffee chain makes federal workers feel less isolated.

Similar to many Starbucks across the country, the most popular products include the vanilla latte and lemon poundcake.

Read WashPo's full investigation here.