DIVER'S MILIEU is a term used to describe the environment in which a diver operates. It consists of three parts: the SKY, the SEA, and the deepsea. The SKY provides the light and air necessary for a diver to work safely, while the SEA is the body of water in which the diver works. The deepsea is the area of the ocean that is deeper than the surface and is often home to a variety of marine life. All three components of the diver's milieu are essential for a successful dive.