Oceanographer Jacques Cousteau began making a series of documentaries that aired on ABC from 1968-75, usually on Sunday nights, under the title, The Undersea World of Jacques Cousteau. If memory serves me correctly, the series, after production ended, moved to PBS, where reruns aired well into the 90's. The sample episode you'll see is a 1991 reissue under a different title. Alan Landsburg, who'd later score hit series with In Search Of..... and the sitcoms Gimme a Break & Kate & Allie, served as an executive producer with Cousteau, though I seemed to think that David L. Wolper was also involved in the series at some point.
As we noted before, the series was an inspiration to singer John Denver, who wrote his mid-70's hit. "Calypso", in honor of Cousteau. For American audiences, Rod Serling (Twilight Zone, Night Gallery), whose last creation, The New People, would air on ABC in 1969, served as narrator.