Von Richter's time machine

Von Richter's time machine was a unique space-time vessel built by the human scientist Von Richter, the culmination of many years of work. It was huge and box-shaped, with a spacious interior. As a prototype, the machine could not be steered precisely: it could take its pilot to "the past" and back again safely, but the specific date of arrival would be random.

Von Richter's machine got its one and only test flight when the scientist finally made up his mind to show his creation to his skeptical friend Ludvig. After Von Richter pulled the lever to send the machine on a journey through time, it rapidly whizzed past millennia of history, being glimpsed as a glowing streak of light in the sky in many eras, such as by cavemen, Vikings, medieval knights and Victorians. However, its trajectory was a "circular" one and it coincidentally ended up landing back where it had started. When they stepped out, Von Richter and Ludvig believed that the machine hadn't taken off at all, and Ludvig convinced Von Richter that he had been wrong to believe time travel was possible. A dejected Von Richter disassembled the machine and pledged to spend the rest of his life on purely theoretical work. The Fourth Doctor would later become aware of this "time tale". (COMIC: Dr. Who's Time Tales)