I'll quote part of a previous answer of mine here:

Conspiracy theories are not unique to the US, nor are they even unique to the Western world.

I can say the US has outsized influence in spreading their own conspiracy theories, but that's simply because US has an outsized influence in exporting culture. (This is similar to the "Florida Man" effect -- there seems to be an excess of bizarre criminal behavior from Florida, but transparency laws are what let us learn about them in the first place.) There are buckets aplenty of "local" conspiracy theories both in recent times and in the past.

In Portugal, there is a pseudohistory theory that the Portuguese made voyages to the Americas pre-Columbus. The idea (first formulated by the historian Jaime Cortesão in 1924) is that the Portuguese government kept up a policy of secrecy in order to hide the existence of the Americas and gain advantage.

I wager a fair chance (assuming you are not from Portugal) you haven't heard of this conspiracy until now; it's pretty much only known locally. But it is very well known locally! It is big enough that it has shown up in school textbooks as fact. There is an inscription in Lisbon:

João Vaz Corte-Real – Descobridor da America

that is: João Vaz Corte-Real, Discoverer of America. There are throrough debunkings by Portuguese historians, but the story still persists.

(Again, this is only a 20th century theory. Incidentally, when the actual era in question was happening, there were plenty of conspiracy theories via Portugal, but antisemitic ones.)

It's possible you've heard the "Mandela Effect" conspiracy theory where people remember Nelson Mandela dying in jail; this is supposedly evidence some of us are visitors from a parallel universe. ("Berenstain Bears" vs. "Berenstein Bears" is part of the same thing.)

In South Africa they have their own "Nelson Mandela died" theory, but since he was President of South Africa and they do remember that, it's a bit different. Supposedly in 1985 Mandela died and was replaced by an imposter: Gibson Makanda. This may or may not have been the work of the Illuminati, and it means, multi-dimensional-chess style, that the one who led the African National Congress against the National Party was actually a puppet of the National Party.

Some of the conspiracy theories are hard to "translate" for other cultures. In Java (one of the islands of Indonesia) in 1998, there was a bizarre set of hundreds of incidents where people dressed as ninjas were knocking on doors, leading to a mass hysteria that they were sorcerers. (Or hunting sorcerers; conspiracy theories can be contradictory.) There was a series of accusations of witchcraft, culminating in 120 people being massacred.

Conspiracy theories are not unique to any place, they just take on their local character. Of course, circumstances across time and space can have uncanny resemblances, so let's do one more--

There was an outbreak of plague in Marseilles, France. England went under quarantine, using the advice of the doctor Richard Mead. Affected areas were to be sealed off for 20 days. Paranoid conspiracy theories about the over-reach of government becoming a "dictatorship" started to spread; some thought the British were in fact immune. People started to doubt the medical experts and turn to the words of religious leaders.

This was 300 years ago, in 1720.

...

Selected Reading:

Portugal discovering the Americas early: Fritze, R. (1994). The Pseudohistory of Who Discovered America. Skeptic, Vol. 2, No. 4.

Portgual and antisemitism: Soyer, F. (2019). Antisemitic Conspiracy Theories in the Early Modern Iberian World. Journal of Jesuit Studies, 6(3), 512-515.

Nelson Mandela imposter: Shoki, W. (2020). On conspiracy theories. Africa Is a Country.

Java and the sorcerer ninjas: Siegel, J. T. (2006). Naming the Witch. United States: Stanford University Press.

England under quarantine: Krischer, A (2020). History does not repeat itself? How an early modern epidemic led to conspiracy theories and religious punishment fantasies. University of Münster (working paper).