Without doubt, it is The African Queen (Humphrey Bogart & K Hepburn) which I saw first as a child, but didn't appreciate until an adult. It has the most profound sequence. The two steam down a river with the idea of making the boat into a carrier of homemade torpedos to ram into the German bully gunboat, the Louisa, which dominated this huge African lake. But when they get to the mouth of the river, it makes a very complex delta with tall reeds blocking view, a maze of intersecting streams, so that Bogart can't find his way into the Lake itself. They labor to get out of the maze and into the Lake in vain. Bogart gets a bunch of leeches on his body from being in the water.
They give up hope and believe they will die, lost in the maze. But then Katherine prays on her knees. They go to sleep exhausted. Then we get God's View from on high! About 20 feet from where they are is the lake, but they can't see it for the reeds. While they sleep a thunderstorm bursts loose. In the morning they find themselves in the Lake and out of the reeds, moved by the new water. It is so figurative of our unsolvable problems, which are nothing to the Lord so far as solving them goes.
Out in the Lake though, at once they see the Louisa in the distance steaming towards them. So what do they do? Back into the reeds they go to hide! Once once trouble is over, and you enjoy the blessing of the Lord, don't be surprised if the enemy has a new one for you!
This is the most theological moment in a Hollywood movie I ever recall, outside a Bible movie.
Forbidden Planet and When the Earth Stood Still are high on my list.
But boy I was skeeered of the interplanetary robocop (Gort) in WTESS. I had like bad dreams of him coming after me wherein I never remembered: Klaatu barada nikto