2. John Wayne - Genghis Khan (The Conqueror)
If I say "John Wayne," you probably think about all of his most famous western characters blended into one, because - let's face it - Wayne's range wasn't amazing, but the man was an icon, so it didn't really matter. This matters, though, because it's absolutely ludicrous in every possible sense: the most American actor in the history of being an American actor wakes up one day and thinks, "I'm going to play Genghis Khan." Are you, John? Shall we talk about why you want to do that before we get too involved?
Aaaaaand,
it's being filmed... This is, therefore, about as miscast a movie as they come. Wayne doesn't really bother trying to infuse this performance with anything even remotely "Genghis Khan," either, though occasionally he does attempt a foreign accent, which basically involves the actor slowing down his sentences and emphasizing words at random, 'cause you know, Mongol. There's also the unhappy matter of the tan that Wayne sports for the entire movie. This is one of those "timeless classics" that deserves to be deleted from our Earth history books, in case aliens land and want to have a look at our achievements and stuff.