Cousteau was a very important figure in deep sea exploration. The French oceanographer studied life 'under the sea', where few people had dared to venture before and instead of just taking samples and writing after the fact, Cousteau was a very prolific filmmaker. His filmed exploits inadvertently popularised sport diving.
Both of his documentaries, 'The Silent World' (1956) and 'World Without Sun' (1964), redefined nature filmmaking and took home Best Documentary Oscars while giving the masses a glimpse of the depths of the sea in colour. Furthermore, he co-developed the aqua-lung in 1943 to allow divers to breathe underwater more easily.