Most of us can agree that real time travel—the use of some kind of machine or portal to go either back into the past or jump ahead to the future—is not something that’s going to happen. At least not until we learn how to dance with wormholes.

But that’s not stopping some people from trying to make actual working time machines and achieve that seemingly impossible dream of science fiction fans all over the world…and perhaps beyond.

A new documentary is being made by director Jay Cheel titled How to Build a Time Machine, and it follows two men who have devoted their lives to building time machines.

You can read a description and watch the trailer below.