The thought of dipping below the surface at night seems mysterious, yet so alluring. Although you've been scuba diving at a site many times before, at night you drop into a whole new world and watch it come to life under the glow of your dive light. The scene changes as day creatures retire and nocturnal organisms emerge. If you've wondered what happens underwater after the sun goes down, sign up for the SSI Night Diving & Limited Visibilty Specialty course.