Topsy-turvy Christmas trees are all the rage right now, dangling from the ceilings of exclusive hotel lobbies and public atriums from London to Vancouver.

A glittery, gravity-defying display at Vancouver International Airport has attracted attention on social media. It's aping the trend of upside-down trees from San Francisco to London, where the tree at the exclusive Claridge's Hotel is designed right down to its gilded roots by fashion icon Karl Lagerfeld.

Some people joke the trees look like they were decorated after a few too many eggnogs.

Space saver

But others are concerned the inverted holiday trees are sacrilegious.

Historians are reassuring.

It turns out the urge to invert the pine is nothing new.

In the 19th century, people sometimes hung small trees from the rafters — which more houses had back then — for a very simple reason: floor space.

"In the small common rooms of the lower classes, there was simply no space," Bernd Brunner wrote in his book, Inventing the Christmas Tree.

Whether done to save space or to keep pets and children away from the ornaments, it's a thing now.

An expensive thing.

A faux, pre-lit tree can be ordered online for between $200 and $1,200, depending on the size.

While the trees are selling out this year, the urge to flip the fir has much deeper roots.

Bringing a fir indoors was a way to upend winter and celebrate Saturnalia — or the winter solstice — by the Romans back in the 5th century.

Legend has it an 8th century English monk who brought Christianity to Germany and France used an upside-down pine to try to turn Pagans on to a new faith, according to multiple Catholic publications and Father William Saunders in his story, The Christmas Tree.

As the story goes, he arrived to find people idolizing Germanic divinities — such as Thor or Odin, who in Norse mythology ruled war and death.

They were preparing to celebrate the winter solstice by sacrificing a young man under a sacred oak tree.

So St. Boniface chopped it down, according to legend.

In the "Thunder Oak's" place — the story goes — a fir tree grew.

Boniface is said to have hung the tree upside down and used the triangular shape to explain the Holy Trinity.

Sacred symbol turned fashion accent

That tradition was still around 100 years ago in parts of Europe, some historians say.

Authors Barbara Ogrodowska and Urszula Janicka-Krzywda both describe how a tree or the top of a fir were suspended from the ceilings in many Slavic homes at Christmas. It was called a podłaźnikiem or (pod-wahz-KNEE-chek).

But the newest trend of precariously dangling a pine from the ceiling is more of a fashion thing.

Perhaps a space saver, but hardly occult.

So nothing to fear, unless it falls.

Except, pity the poor person who has to figure out how to secure such a prickly, heavy thing from the ceiling — now that most homes do not have sturdy rafters and low ceilings of old.

Upside Down Christmas Trees 20171205

An upside-down Christmas tree is suspended from the ceiling at the Fairmont Vancouver Airport hotel in Richmond, B.C. (Darryl Dyck/Canadian Press)