SCUBA is an acronym for "Self Contained Underwater Breathing Apparatus". In short, scuba diving is strapping a tank of air to your back out of which you can breathe air so you won't drown. SCUBA was co-invented by
Jacques Cousteau and [Emile Gagnan]
? in 1943 as the
Aqua-lung.
The maximum safe depth for use of normal scuba gear is between 30 and 50 metres, before nitrogen narcosis becomes a danger, even with Enriched Air Nitrox.
One global organization for Scuba Diving is PADI, who can be seen at http://www.padi.com/