"While Hollywood in the 1960s was fantasizing about it with their science fiction films, Jacques Cousteau’s adventure was already underway. The project was known as Conshelf, with a goal to send up to ten aquanauts to live in the sea for one month inside a habitat filled with oxygen and helium. The first habitat, Conshelf I, made history in 1961 when two divers of Cousteau’s Calypso team lived in a small underwater habitat the size of a shipping container at 37 feet deep for one week. The drum-shaped structure had a hatch for the divers to enter and exit their underwater home to carry out research on the seabed.
Only a year later, Conshelf II was born in the Red Sea off the coast of Sudan. This time, six divers would live for month underwater, without sunlight in a starfish-shaped house. A smaller and deeper cabin housed two oceanauts for a week at 82 feet."
https://www.messynessychic.com/2013/05/27/remains-of-an-underwater-habitat-left-by-1960s-sea-dwellers/
Only a year later, Conshelf II was born in the Red Sea off the coast of Sudan. This time, six divers would live for month underwater, without sunlight in a starfish-shaped house. A smaller and deeper cabin housed two oceanauts for a week at 82 feet."
https://www.messynessychic.com/2013/05/27/remains-of-an-underwater-habitat-left-by-1960s-sea-dwellers/