Nancy Holt, Boomerang (1974), still from video.
In her time on this planet, Nancy Holt came to be known as a great American Land Artist, and certainly her brilliant installations, like Utah's Sun Tunnels and collaborations with her partner Robert Smithson and their peers, are profoundly significant, but it was her work in film & video that has had the greatest personal impact on me.
I somehow didn't see Boomerang, her 1974 video performance usually credited to her collaborator Richard Serra, until I was a Ph.D. student in Linda Williams's Phenomenology of Film seminar at UC Berkeley's Rhetoric program, but the time delay was more than made up for by the work's formative resonance. In the video, made during Serra's residency at a Texas television station, a young Holt is seen sitting in an anchor's chair before a staid blue background. Despite brief station ID graphic overlays and one minute of silence in the midst of the ten-minute piece (announced as audio trouble and reminding viewers of the work's live TV origin), the work is in many ways sound-centric.