Based on the film of the same name, this was the first, and longest-running, of Irwin Allen's sci-fi quartet.
David Hedison and Richard Basehart starred as Captain Lee Crane
and Admiral Harriman Nelson
in the undersea exploits of the Seaview
Season 2 onwards was filmed in colour and from this point on there was a gradual increase in the number of fantastical storylines, with the final season featuring more aliens than the average episode of Star Trek