Queen Elizabeth II meets children making Halloween cakes in Lewes, England. (Chris Jackson/Getty Images)

Halloween is a controversial day in Australia. The holiday is not traditionally observed there widely, but kids are still aware of it from TV and movies. So, every year, an increasing number of Australian children dress up in costume and go door-to-door for candy, as the grown-ups debate whether they should continue to resist the foreign cultural imposition.

"If any children approach my building, I’m just going to silently admire them from the intercom screen and pretend that I’m not home. I won't be the only one," Australian writer Van Badham declared in Wednesday's Guardian, as part of the annual Australian tradition of refusing to enjoy Halloween. "For people like my mother, it’s a deliberate rejection of the kind of U.S. imperialism that suckered her generation not into witches hats and candy, but Australian participation in the Vietnam war."

Badham goes on to note that, even if you don't see Halloween as American cultural imperialism, it's still awfully unseasonal for the South Pacific. The holiday is full of autumnal iconography, but October is springtime in Australia.

The annually recurring Australian Halloween debate actually raises an interesting question: Why is it that the United States and so many other countries celebrate the holiday, but Australia does not? The answer is kind of fascinating: It turns out to be a weird historical quirk of British colonialism and of Britain's brief but world-changing experiment with severe social conservatism in the 19th century. Those two British forces, it turns out, have actually shaped much of the world's Halloween customs today.

Halloween's origins go too far back in history to be known with absolute certainty, but historians generally agree that it began with Celtic-speaking people on the British Isles. It's an especially big deal in Ireland but has also long been observed, in some form or another, among the English, Welsh and Scottish. When British settlers headed over to the new world in the 17th and 18th centuries, they brought the Halloween tradition with them. That's why Americans and Canadians celebrate the holiday today.

The irony is that, while the British were responsible for spreading Halloween, they also spent several decades trying to stamp it out. In the latter half of the 19th century, Great Britain experimented with a form of social conservatism known as Victorianism, after then-monarch Queen Victoria. The strict Victorian social code called for, among other things, a rigid class hierarchy, gender roles that privileged men over women, sexual restraint, an obsession with manners and a deep disdain for all things that might be perceived as indulgent. One of many things to come under Victorian suspicion was Halloween, filled as it is with superstitions and flamboyant costumes and other forms of fun. So the holiday fell out of favor for a while.

The Victorian backlash against Halloween just happened to coincide with much of the British imperial expansion. That included the colonization of Australia and New Zealand. So the Brits who filed in to these new colonies in the South Pacific didn't bring the Halloween tradition with them. One also wonders if they didn't import a certain Halloween skepticism that might explain their continued resistance to the holiday, long after much of the rest of the Western world has adopted it.

Victorianism spread more than Halloween skepticism, of course. Social scientists who study Africa, the Middle East and South Asia often argue that these regions are today some of the worst societies in the world for women and for gays because 19th-century British colonial overlords ingrained their legal systems and social codes with those very Victorian ideas. And those have persisted.

Then why didn't Victorianism wipe out Halloween in the United States? By the time the Victorians kicked off their anti-Halloween campaign, the American colonies had already broken away from the crown.

You can see the legacy of British imperialism in other Halloween traditions around the globe. Hong Kong and Singapore, the two East Asian city-states long a part of the empire, are both known for their raucous Halloweens. While both, like Australia, were established during the Victorian era, perhaps the difference is that they remained British possessions after Victorianism ended around 1900. As the holiday returned to early 20th-century Great Britain, it may have been resurrected as well in Hong Kong and Singapore. But Australia and New Zealand became independent commonwealths in 1901 – the same year that Victoria died and her namesake moral code began to ebb. So the post-Victorian resurrection of Halloween that happened in Great Britain may have never had a chance to spread directly to Australia and New Zealand.

Of course, more recently there's been a second wave of Halloween proliferation, as American culture has spread the holiday far and wide. That's been particularly true in developed countries that consume a lot of American movies and TV shows, such as Western European nations and Japan. Countries with American military bases, such as the Philippines and South Korea, also seem to have relatively well-observed Halloweens, although it's not clear if this is a direct product of the presence of American military families or just a coincidence.

You can get a pretty good sense for Halloween's global spread from this map, produced by Quartz, showing which countries see their candy imports peak during October. It's a clever, indirect method for measuring where Halloween is most popular, although candy is not central to all versions of the holiday:

Countries marked in pink see their candy imports peak in October. (Quartz)

You may notice a few former British colonies marked in pink, such as Kenya. While Thailand was never colonized, it came under heavy British imperial influence, and American culture is popular there, as well. But even if the Americans are more to blame for Halloween's spread to a lot of these countries, such as Russia or Chile, it still all goes back to Britain. When American children go out trick-or-treating, they're following a tradition from their nations'  English heritage. And when Australians refuse to celebrate "Americanized" Halloween, they're actually resisting an originally British holiday and holding on to Victorian ideals that died out over a century ago.

This little quirk of global cultural trends is a reminder of just how deeply European imperialism, particularly of the British sort, shaped our world, and in ways that we normally wouldn't think to consider as colonial artifacts. But they are.