Trivia

The destruction of the underwater city utilized stock footage from Atragon (1963).

This filmed adaptation of an Edgar Allan Poe source poem was green-lit with the intention on cashing in on the 1960s cycle of Poe pictures. This had been a decade which had already featured seven Poe pictures first released prior to this 1965 movie and every one of them had starred Vincent Price who also headlined this Poe picture.

Star Vincent Price didn't see the script until six days before shooting began.

John Le Mesurier replaced Boris Karloff in the role of the Reverend Jonathan Ives.

This movie is alternately titled in English speaking territories by at least three or four different titles: "City in the Sea," "The City Under the Sea," and "War-Gods of the Deep" (aka "War Gods of the Deep").