Apologies if these were already posted but these are short movies I thought some would enjoy. Pasting teh web address will allow you to view the films or downloading them in one of the formats listed.
"Man In The Sea" 13 min long, nice footage of deep diving previous to 1969.
https://archive.org/details/maninthesea
"Frontiers", 1965, Hearst Metrotone News, Inc, Shows highlights of the space mission of Gemini 4 and the undersea mission of SeaLab II
https://archive.org/details/frontiers1965
1956 Manfish ( Lon Chaney Jr.)
https://archive.org/details/1956ManfishLonChaneyJr
The Fathoms Deep; Early footage of French Navy officer Jacques Yves Cousteau demonstrating his revolutionary underwater breathing apparatus known as SCUBA.
https://archive.org/details/TheFathomsDeep
Brad Matsen discussed the life and work of J. Cousteau from his book Sea King
https://archive.org/details/groks412