Despite how easy it looks in James Bond movies and heist flicks, good disguises are hard to pull off. A good wig and some makeup don't make you a new person—full transformation requires a full attitude adjustment. Just ask any contestant on RuPaul's Drag Race. And when you're a spy for the Central Intelligence Agency, being able to execute a perfect disguise can be a matter of life and death. Just ask Jonna Mendez.

"One of our officers, probably working out of the American embassy, would have surveillance 24 hours a day; they'd have teams of people following them," says Mendez, who spent years as the CIA's disguise chief. "But they had work to do; they had to communicate with people, clandestinely. The extremes we would go to to disguise those people was the most interesting, and the most challenging, part of the job."

So what does the agency do to protect its assets in the field? A lot of it, Mendez says, involves hiding a person's tell-tale features. If they have straight hair, make it curly. If they're young, give them a few streaks of gray. It also helps to change the way they walk or talk by putting a brace on their leg or an "artificial palate" in their mouth. Americans have a certain way of standing—weight on one foot or the other—and if they're trying to pass themselves off as European, it helps if they stand squarely on both feet. Good disguises, Mendez says, are almost always "additive;" you can make someone taller, heavier, or older, but "we can't go the other direction."

The CIA can also give a person the ability to do a "quick change." If someone knows they'll be trying to shake a tail, they can change their look as they move through busy sidewalks. Add a hat, change a shirt, add sunglasses, and—if it's done right—it'll look like someone has disappeared.

"You want to be the person that gets on the elevator, and then gets off, and nobody really remembers that you were even there," says Mendez, whose husband, Tony Mendez, was the subject of the 2007 WIRED story that became the movie Argo. "That is a design goal at the disguise labs at CIA."

Check out more of Mendez's tricks in the video above and in her Reddit AMA here.

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