1923 Men Like Gods
Roman authors were the first to write alternate histories—tales of what the world might have been had historical battles ended differently. But stories about alternate worlds that exist simultaneously with our own came much later. H.G. Wells (pictured here) becomes the first to write a science fiction novel that uses a concept similar to Everett's theory of parallel worlds. In Men Like Gods, several English motorists inadvertently drive through an invisible barrier and cross into a parallel world. This alternate world's inhabitants, whom the travelers call "Utopians," explain that their universe split from ours 3,000 years before, and that their world and ours are only two of a vast number of parallel worlds.