After all, what would this conspiracy theory be? It's actually a speculative hypothesis about something, or about something that people have discovered through secret and want to pass on to other people about that such an event.
Many believe that Covid's vaccine has a chip, and that the virus was created in the lab and then released around... There is strong evidence that this is true, but since the vaccine has a chip it is a lie, as what would be the reason to put the chip in if in fact we are all fighting this terrible pandemic that doesn't seem to want to end.
Most conspiracy theory is nothing more than an attempt to make people afraid and living in uncertainty of a possible threat.
This fear creates within the human brain a certain paranoia that can make people paralyzed with fear and make people be inclined to spread a false hypothesis. Often this paranoia causes collective harm.
You should say "a conspiracy theory" or "conspiracy theories" in the title. Have you ever heard of the Ides of March? Those who don't believe any conspiracy can happen are ignorant of life and history. If you think several planes were hijacked simultaneously and then sent to attack several buildings had some kind of planning behind it then you believe in a conspiracy.
Thanks for your tip @leprechaun... Look, many things that happen are really strange, for example simpsons, how can he predict in advance what will happen and does it really happen?