The Doctor and Sarah Jane meet the Doctor and Sarah Jane.
A parallel Earth was an alternate universe that was once visited by the Third Doctor and Sarah Jane Smith in the 1970s. At that time, Edward IX was king of England. Parallel versions of the Doctor, a human who did not recognise the TARDIS and was unaware of extraterrestial life, and Sarah Jane existed in this universe. The parallel Earth was also home to at least one car which had a solar powered engine, which the N-Space Doctor stated would not exist on the Earth of their universe for another century (ca. 2070s). (COMIC: Who's Who?)