Fantastic Voyage (1966)

  This is a much more well-known sci-fi film, though I wonder now how many of the 90s and later kids will have seen it.  The visuals still hold up even if the plot is terribly dated.

Grant (Stephen Boyd) safely shepherds an important government VIP through an assassination attempt but learns that the scientist is gravely injured with a clot in his brain.  Grant is tasked to join an incredibly secret mission and provide security to a team of doctors who will be shrunk and inserted into the comatose scientist's bloodstream.  They will have less than an hour before the procedure wears off and they begin growing back to their original sizes.  Grant is also warned that the lead scientist, Dr. Duval (Arthur Kennedy), is arrogant and headstrong and may in fact be a double agent intent on sabotaging the mission.  Sure enough, things start to go wrong almost as soon as the journey begins and Grant must ferret out the identity of the saboteur, and ensure the safety of the crew as well as the success of the mission if the U.S. is to retain exclusive knowledge of the shrinking procedure.

This is a great little Cold War gem that highlights the extreme paranoia so prevalent at the time.  I don't think it's a stretch to say that it's the primary function of the film.  Zero attention is paid to any background on the program, the scientist himself, or the aftermath of the mission.  It is strictly focused on the voyage and the possible saboteur.

As time has passed, those motivations seem less dramatic but the ticking countdown does retain a lot of the original tension.  The anxiety of the waiting surgical staff, the sweaty fug of the military leaders responsible for pulling the plug on this project, and the snap decisions made by the tiny argonauts are factors that contribute greatly to this being a sci-fi classic.  The internal visuals of the human body do the rest of the work, as organs become vast Rube Goldberg machines of destruction for our hapless protagonists.

I had seen this as a kid and even been on the ride at EPCOT that was totally based on this movie even though Disney didn't produce it.  It's one of my mom's favorite movies.  I had forgotten how abrupt the ending is until I rewatched it for class, but it's still definitely worth passing on to the next generations.