According to DS9, the aliens at Roswell, NM were Ferengei.
According yo Futurama, it was the Planet Express crew. (Aww Hell, one could make an entire book out of TV shows/movies that said their “thing” was what happened at Roswell.
And according to Voyager, the microprocessor revolution was the result of a single man ( :rolleyes: ) stealing technology from a time ship from the 29th century that crash landed in 1960’s Earth.
Who continues to steal, er, “buy” technology to this day. 
According to The Forge of the Titans, all those studies showing psychic powers to be ineffective/nonexistent were fabricated by the government to cover up it’s own quite successful research.
Every time traveler sooner or later ends up shooting Kennedy.
In Anthony Burgess’ Kingdom of the Wicked Jesus is made out to be just an impressively hard bastard, who can simply survive the crucifixion. Muscular Christianity indeed.
In one of Spider Robinson’s Callahan’s Place novels, Hitler was a disguised alien, acting as part of a plan to manipulate us into self-genocide; WWII was supposed to be nuclear.
In James P Hogan’s Giant’s Star, history and society have been heavily manipulated by the Jevlenese, a bunch of humans presently living on another planet who acquired high technology millennia ago ( long backstory ).
In Mutineer’s Moon by David Weber, much of history has been manipulated by two opposing super-high-tech factions. So several of the characters have names like Horus, Geb, Anu, Inanna; and the naval uniform of the interstellar Fourth Imperium bears a close resemblance to the Nazi’s SS uniform.
In one of the Kzin War stories, it’s mentioned that Communism was created as an attempt to retard technological progress, by the Order, the undercover precursor organization to the ARM. And Nazi Germany was a tool of a renegade faction of the Order.