Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964 IMDb)
One of those cases where the quality of the special effects actually and consistently does hurt the experience of what is otherwise ingenious.
References here: Fail-Safe (1964), Bureau of Proto Society (2015), HyperNormalisation (2016).
Viewed 2018-01-17. Ugly in unsafe old browsers.