A 1954 classic from Universal Pictures. People argue it wasn't Sci-Fi but horror. I disagree. The entire movie was based on science fiction, and very little horror if any. Kinda like the very first Star Wars. I saw Luke's aunt and uncle's corpses still smoking on Tatooine. Saw Han shoot Guido, leaving his corpse also smoking. Saw Ben slice off that guys arm in the same tavern, using his lightsabre. Did all that carnage make it horror? Nope.
The same for this movie. Did modern man come from the oceans? Is that why we can't find the "missing link" on land? Are there more of what we used to be thousands of years ago in our oceans? Our waterways? Was Atlantis real? All Sci-Fi.
Anyway, the inspiration for this movie was the 1941 creation of "Aquaman" by DC comics. But in the production they wanted a more scientific approach, not mythology (Atlantis). Hence the "creature" has legs and walks like a man, has arms and hands, but also resembles a fish.
The movie was an instant hit. To those scientific minds, was it possible we once lived under water? They made 2 sequels but they were not as good as the first.
Also there is Julia Adams. How can you NOT want her? Seeing her in that bathing suit and swimming, I forgot all about the creature until he notices her too!
Lastly, if you wish, watch the movie here. It's free:
Link