Simon and Kirby put together the Black Magic horror comic for Prize Comics in the fifties, and there was at least one time-travel story, “A Hole in His Head” by none other than an early Steve Ditko. That story was based on a 1951 TV episode of Lights Out (“And Adam Begot”) written by Arch Oboler and taken from the 1939 radio show Arch Oboler’s Plays.

Simon and Kirby created The Fly as part of Archie Comics attempt to ride the silver age superhero craze. He flew through time at least five times, with the first episode (in issue 8, no longer Simon and Kirby) being a trip to 3rd century Persia. The Jaguar also trekked at least six times starting in Pep 5 (Oct 1961) and continuing in the Man of Feline’s own comic book, Adventures of the Jaguar as well as Laugh Comics. And the Shield had some time-travel adventures, beginning in The Fly 37 (May 1966) where he met a gladiator from the future.

Given that the Time Stone is a key element to Thanos’s master plan, you’d think that time travel would play a major part in this movie, but not so. Doc Strange does use the stone to view a slew of possible futures, but we know that’s not actually time travel. So where does the time travel come into play? Pay close attention to the final thirteen minutes of the film, after Strange announces “We’re in the end game now,” and you’ll spot one definite time travel moment and a second possible moment.

After the devastating events of Avengers: Infinity War, the universe is in ruins due to the efforts of the Mad Titan, Thanos. With the help of remaining allies, the Avengers must assemble once more in order to undo Thanos' actions and restore order to the universe once and for all, no matter what consequences may be in store.

The Watcher tells us of a universe where a change in a single decision made Peggy Carter (rather than Steve Rogers become the Allies’ super-soldier. Like Steve, Peggy also managed to find her way into modern times via a technique that’s related to time travel.