Time travel isn't necessarily forbidden by physics, but it can be explored through wormholes and curved spacetime. Sci-fi writers have come up with numerous methods to navigate the space-time continuum, including iconic cars and spaceships, and even a time machine built into a hot tub. The most powerful and sophisticated time machine of all is a Time Lord's TARDIS, which can travel anywhere in history (or the future) when it comes to a certain point. However, due to the complex calculations required to reach this destination, the use of a DeLorean for time travel is not as easy as it once was. Other notable examples include the Volkswagen Beetle and Cadillac Eldorado driven by Austin Powers. Despite this, the rules no longer apply in the MCU, where time travel does not change the future.