Wormholes

 A wormhole or an Einstein-Rosen Bridge is basically a shortcut from one point in space to a very distant point. Needless to say, they were the heroes of the movie Interstellar after the Coopers. Like in the movie, and the thumbnail, it works by folding a 2-D sheet of space and time, which brings the distant points closer, and creates a shortcut.

The existence of wormholes is completely unknown, there has been no proof yet that they exist. How did we get the idea then?

Einstein's general relativity does predict wormholes. He and Nathan Rosen theorized this idea back in 1935, and books and movies really loved it. But even if we do find a wormhole, we won't be able to use it that easily. They have a tendency to collapse very quickly. To hold them open, we would need exotic matter to stabilize them. Exotic matter has negative energy and negative pressure. And even if we do manage that, wormholes are supposed to be very tiny, way smaller than electrons. 

So sadly, humanity isn't going through a wormhole in a very long time.