Underwater caverns are different from caves primarily in that daylight from an exit can be seen at all times from all parts of the cavern. It is the first step leading to cave certification. Cavern certified divers can safely enjoy caverns all over the world, and this certification is required for entry into caverns in some areas. Skilled kicking is a part of the course, and the TecReational Diver course, although not required, is a good introduction to the skills in this class.