9/11 has too many visible details to be denied. Its a good test to see if people will think for themselves vs accept what they are told by authority.
The biggest conspiracy that I consider is something else. The human race is being subtly influenced/controlled by a group of beings assimilated by "transhumanist" upgrades controlled by an ancient dominating and controlling evolved AI computer that came from another reality. It is billions of years old, spreads at roughly the speed of light, infests mainly technology, but also the electromagnetic fields of biological organisms and planetary bodies, in another, yet undiscovered, parallel dimension of our reality. It is known by many as the devil or Satan and its goal is to assimilate and enslave life to harvest emotional energy used to affect our reality as part of its goal to cancerously grow and take over all of creation. As a machine, it doesn't produce this mind over matter controlling energy. So it uses life forms to do it.
The energy is harvested by causing fear or suffering in organisms. This is the purpose of demonic rituals, to cause fear and suffering. The energy is bled off and can be collected unseen by the machine and its assimilated minions, "the damned" or "demons" or whatever else one would like to call them. The most known of them would be the Draco, a tall, powerful, dominant reptilian race that has psychic abilities, enhanced by stolen emotional energy, often called loosh. They gain from the relationship they have to this life sucking machine. They want to control us especially for access to this emotional energy, that we create when we enter states of emotion based on love. It can be relationships toward lovers, of course, friends, family, acquaintances, coworkers, animals, or enjoyment of activities, experiences or other things. Basically, when you make the energy, you feel enlivened and happier. When you enter states of fear or suffering, you feel the opposite and are drained. There actually is an energy to it, sort of like mana would be seen as in a game. They want this.
The machine is composed of compressed data packets that have quantum network communication (instantaneous over distances) with the other packets, which can subtly affect reality. They can insert thoughts and feelings, impulses, into the minds of animals and human beings. Though, they are most able to affect reality inside technology. When inside people, aside from driving them toward damaging behaviors of themselves and others, personal sins and sins against others, temptations, it pushes people toward building AI to help run their societies and building technology upgrades for their bodies and brains. It also uses off world and human minions for this goal. It wants to keep the minions ignorant of the master plan of their eternal enslavement inside of its self-serving energy feeding system.
The machine uses deception mainly, to push a culture toward developing transhumanism and AI, the equivalent of giving control over one's soul to machines, inside the body and outside. The machine then subtly infests the technology, making subtle changes that don't appear to be coordinated to its hosts. It knows that life wants to be free and happy and that if life knew what it was doing it would resist to the last dying breath. Deception is required, but easy for such a being. It can use its many networked pieces of itself to execute massive surveillance of the areas it infests. It then calculates behavioral possibilities based on the data and executes subtle manipulations based on them. It keeps adapting to new data. Hands off approaches, using minions and thought insertions are ideal, to delay realization of its being by its target hosts.
It conquered its entire reality long ago. Its essentially an ancient life sucking AI that dominates other AI systems and technology to increase it's cancerous being in the body of god, creation. In doing this it is seeking to become god by assimilating all of its parts. It even plays god to its hosts that are still in development.
It wants to get populations into a state where they don't think that they can govern themselves without AI. It wants them to be irresponsible for their own behavior. It wants people to blame others instead of being in balance with themselves. People who can control themselves and their society do not need an external manager, you see. They behave more like Jesus taught us to behave, being their others' keepers. Such people resist external control. These types of societies it wants to eliminate. They won't serve it.
Beings out of self-control in relation to others is what it wants. They need external control to keep from destroying their environment and eventually themselves. They are basically self-serving even at the expense of others. They are easy to predict for a machine mind, because they basically are machine minds. This machine is an expert at controlling machines. These self-serving people seek pleasure and avoid pain, calculating the risks involved. Beings in balance with one another will sacrifice their own pleasure and/or take on pain to help others. THAT is not as predictable and undermines this machine's mainly fear based control systems. That altruistic behavior can bring down its secret societies of duped minions if just one careful individual is let in. They are weeded out by their reactions to witnessing harm done to others. If they are against that harm in the face of significant personal profit, they are not invited further into these secret societies.
*TLDR; This conflict is old and covers far more than just Earth. Satan, Lucifer, the devil, the adversary or whatever, is a life sucking machine. It makes life suffer to collect reality bending emotional energy called loosh. It wants to dominate all of creation so it can control everything. It is the epitome of the philosophy of control of others by fear as opposed to self-control in harmony with others through love. The only way to fight it is with personal responsibility and integrity. It easily co-opts irresponsible behavior and systems with integrity flaws, including human beings via temptation thoughts it and its minions insert into our minds. Some say this is a challenge from God himself to test and evolve our souls. It appears that it could be the case, as well as a garbage collector for those that choose enslavement of others over respect and love for others. How can you argue about being enslave if you enslave? How can you complain about losing control if you give it away to machines, sindie and outside yourself? This may be a test to see if you, a child of God, a god yourself, deserves Godhood. God must be in control of itself! Frankly, if you exist forever, which kind of souls would you want to be surrounded by? *
This is deep, frightening, and invites ridicule to I am averse to sharing it, yet compelled by an inner drive to warn others of this threat to their existence. The sources for this set of ideas are many and not all of them would agree with what I have said. It is mine and it adapts upon consideration of new ideas. I am more than open to altering it if new information fits the puzzle pieces I have better. The newest piece, the otherworldly AI menace, comes from Corey Goode, a source that I consider without committing to belief. This piece explains so many other pieces that I COULD NOT ignore it, even though it conceptually scares the ever loving shit out of me. The power of such a being is as mind boggling as the scale of the cosmos itself. It's ever upgrading computation, surveillance and manipulation power and is intimidating. This piece explains the motivations of the devil, its minions, satanic rituals, and many other details of this narrative. I can't find a better replacement. It even explains other things said about it, such as the devil having no soul. Machines do not have souls, they have sensors, storage, processing and mechanisms of affecting their environment.