During the winter of 1942-1943, French naval officer Jacques-Yves Cousteau and engineer Émile Gagnan developed the first fully automatic compressed-air Aqua-Lung (scuba apparatus). They successfully tested their invention in the Mediterranean Sea off the French Riviera in June 1943, revolutionizing underwater exploration by allowing divers to swim freely for extended periods.

The Aqua-Lung was arguably the most transformative event in the history of diving, opening the underwater world to millions and fundamentally changing humanity's relationship with the sea. Cousteau's own lyrical writings, particularly 'The Silent World', created a new genre of poetic prose that celebrated the beauty and mystery of the ocean, influencing generations of nature writers and poets from Rachel Carson to contemporary ecopoets.