Man with a Movie Camera

Man with a Movie Camera, an experimental 1929 silent documentary by Russian director Dziga Vertov, is available on the Internet Archive. It is "famous for the range of cinematic techniques Vertov invents, deploys or develops, such as double exposure, fast motion, slow motion, freeze frames, jump cuts, split screens, Dutch angles, extreme close-ups, tracking shots, footage played backwards, animations and a self-reflexive style (at one point it features a split screen tracking shot; the sides have opposite Dutch angles)."

It's ambitious and clear for an early attempt to reveal techniques that might have a magical hold on the unconscious.