Why is Triumph of the Will an example of propaganda?

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Riefenstahl's techniques—such as moving cameras, aerial photography, the use of long-focus lenses to create a distorted perspective, and the revolutionary approach to the use of music and cinematography—have earned Triumph of the Will recognition as one of the greatest propaganda films in history.

Explanation:

which statement explains one of the reasons world war 1 was so much more destructive than earlier conflicts