The first movie I can remember seeing was an underwater sci-fi adventure. I was about 6, in my pajamas in the backseat of my parent's car. I was trying to find the name of the movie, when I ran across War-Gods of the Deep (1965). It isn't the movie I was looking for, but it looked interesting.
It starts with a mysterious death on the Cornish coast. Tab Hunter heads up to the manor house, the usual creepy pile, except it's owned by cute American Susan Hart, who rents rooms to tourists. It all seems innocent enough until a creature draped in seaweed steals her away. So Tab, along with very British David Tomlinson, enter the secret passage to rescue her.
Now, we haven't even met star Vincent Price yet, but let me calibrate your kitsch-o-meter. Tomlinson plays a bad painter and hen fancier, who carries his pet hen Herbert along for the rescue. He is not so much comic relief as WTF relief.
To resume, the secret passage leads to secret tunnels, which lead to a huge, almost deserted underwater city. It is populated by English smugglers from the 18th century, lead by despotic Vincent Price. He rules his band and a school of gill-men, who seem to desire blonde American women. And even though he is competing with a Brit with a chicken, he manages to out-ham everyone onscreen.
The movie is also known as City in the Sea, after the poem by Poe, although the connection is tenuous - Price recites an extract, so we have another Price movie "inspired by" a Poe poem. We also have some rubber costumes and some stock footage, the latter from Japanese kaiju movie Atragon. If this sounds intriguing to you, you know what you want. So go ahead.
It's probably better than the one I saw at the drive-in.