Back in 1982, at the tail-end of the Bronze Age, a pivotal event happened in a second-tier Marvel Comics' title: Doctor Strange #53.
In the story Doctor Strange must hunt down the shard of a piece of the soul of a young woman he loves.The fragment of her soul is traveling back in time skipping centuries to reside in her past lives bodies.
Unless the process is stopped mankind will stop dreaming thus ending the existence of the Marvel villain Nightmare. It is Nightmare that has sent Strange on his time-spanning quest.
Strange soon finds himself in ancient Egypt standing atop the Great Sphinx.
To his amazement he discover that the Sphinx contains advanced futuristic machinery.
Upon closer inspection the Doctor soon finds himself trapped and taken prisoner by a mechanized security system.
Freeing his bonds using his Astral Form, the Doctor travels to the Pharaoh's chamber only to discover the Fantastic Four held captive and unable to use their powers.
Coincidentally he Doctor has traveled to the same time the FF traveled to the past to witness their current predicament.
As the story unfolds Strange finds his love's past form and manages to free the Thing by focusing the cosmic rays from the Sun transforming the Thing into Ben Grimm, who escapes his bonds and in turn frees the other members of the FF.
Doctor Strange #53 shares almost an identical cover with FF #19. If it were not for the aid of Doctor Strange the FF and quite possibly the Marvel Universe as we know it would not exist.
Marshall Rodgers and Terry Austin provide the stellar art aided by the clever Roger Stern script.
I consider this issue one of the most important comic books in Marvel Comics' history . It deserves to be a 'key issue' in any Marvel Comics collection.