Murray Leinster: Sidewise in Time
“Sidewise in Time” is a short story by American writer Murray Leinster, published in June 1934 in the magazine Astounding Stories. A series of inexplicable phenomena rocks the Earth until, one day, reality begins to fracture: ancient forests spring up out of nowhere, dinosaurs emerge from a farmyard, Roman legions march through the streets of Missouri, and Viking ships raid the coasts of New England. While the world reacts in astonishment, a single man seems to understand what is happening: Professor Minott, a mathematician at a small university in Virginia, who has been secretly preparing for months for a cataclysm that threatens not only humanity, but also space and time as we conceive them.