[nitpick]Actually, it was only a little more than twenty years.[/nitpick]
Al Queda Bombed Pearl Harbor.
Orson Welles murdered the Black Dahlia. Suffering from a “diphasic personality”, Welles killed the Black Dahlia in a fit of rage; clues can be seen in an unused set from Lady of Shanghai which shows mannequins in a fun house in poses simimilar to the condition of the body when found.
The strange thing about this one is I didn’t make it up. It’s the pet theory of writer Mary Pacios, a childhood friend of the Black Dahlia’s.