In movies, books, and tv shows, wormholes are described as a way to travel to different places instantly in a sort of portal.
Researching the subject, I found out there are different types of theoretical wormholes.
One type is called schwarzschild wormhole. It was discovered by Einstein and Rosen. They connect two universes and can only be travelled in one direction. Later, a paper was published that showed this type would be unstable if connecting parts of the same universe. It wouldn't be able to stay open long enough to let anything through it.
Another type of wormhole is called traversable wormholes. They can be traveled through in both directions if held open by some type of "exotic matter" (something with negative energy or mass.) It's thought by some that these may have been naturally formed in the early existence of our universe.