In the 1940s and '50s, French oceanographer Jacques Cousteau pioneered the world of underwater exploration with the invention of modern scuba equipment as well as the use of the "indestructible" shark cage. Previously, scientific encounters with sharks were limited by risk, but as Cousteau and his team began diving within the safety of metal cages to avoid the teeth of their underwater playmates, researchers have been able to observe sharks in relative safety, making discovery and filming of the animals regular possibilities.