The Light at the Edge of the World
Throughout the movie, every time a cannon fires there is no recoil.
When being sunk in the end, Kongre's ship is obviously a miniature. Besides, some damage is visible before the impacts (particularly noticeable when the ship is hit in the waterline).
When Kirk Douglas jumps, the dummy's legs flail around, the knees bending in unnatural angles, revealing it to be an obvious prop.
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