This was great stuff for the time. I remember that my family rarely missed this show! Richard Basehart as Adm. Harriman Nelson and David Hedison as Capt. Lee Crane were always searching for new undersea discoveries. These, of course, very often led to adventure and drama. We never knew when the Seaview was on her last voyage. There were often giant undersea monsters to deal with. And, of course, even though they haven't been spotted by man in all of written history, they were THE biggest danger of our time. They obviously had to be dealt with, now didn't they? By today's standards, the special effects were quite laughable but for their day, they did their job. I recall some of these shows even today, decades later.