Some Sci Fi Stuff...apologies to Burroughs, Herbert, Asimov...

My apartment rests on a large ET landing strip.
Millions of years ago, alien ships would ferry small families to live in what is now underground my studio.
Their plans were much like those of early American settlers: mining.
They mined for a substance off the Earth until it was no more, and consequently killed off the dinosaurs.
The substance was used to feed our very large alien visitors. It only took tiny doses cut with vegetation to support their dirigible sizes. But the richer value lay in the substance's beneficial qualities to hive mind populations: telekinesis, ESP, etc.
On their home planet, the substance had been mined away and they had left to go trolling after what might still linger nearby.
After they had mined it off our planet, the visitors left to find another source. Eventually, the substance returned to our planet with a great comet impact and now resides near the Earth's core.
Sometime around 1900, our friends returned when their scanners revealed the substance had returned. After fifty years the visitors returned in larger numbers and with many other species ready to exploit the planet for their own gain.
But now humans posed a challenge.
Finding an intelligent species that would put up a fight, they decided to decimate the population. Any large strike on the planet would not hold well with the powers that kept the law in the galaxy. Therefore, a species of alien was used to infiltrate our many governments to slowly exterminate the human race through more subtle methods.
A great war was first introduced to man and very, relatively, small populations were killed off in an exercise to see how such a plot might be pulled off. Such a plot found major problems and was rethought.
The Bomb was then introduced, not to eliminate the humans, but to control them under a two party world government.
This was a major victory.
Control became the primary objective.
When the mining ships are to finally arrive, some 100 years from now, the populace will welcome them via the conditioning received.
This plot then moved down to religion, race, and nation states. History was soon rewritten to reflect the new power scheme and implanted into humans with key visits to humans that were more in tune with the substance. These "special cases" could link any information the aliens fed them to other humans around the globe.
But there were other agents.
The Galactic Empire had been sent rumor of the plot and sent their own men to investigate and stay on the Earth as peacekeepers.
Most were bought.
The few that were not were cut off from all communications and pronounced dead. Those few that survived carried out a defensive battle by implanting "select cases" with the truth of the invasion.The result was a great schism in humanity. What we find 30 years later is a mass culture of schizophrenia.