The interminable new film “Modern Times Forever” isn’t likely to win any Oscars — or… The interminable new film “Modern Times Forever” isn’t likely to win any Oscars — or even attract many viewers. It is, however, a worthy contender for the title of ultimate cinematic paradox: a movie that’s not meant to be seen.

Clocking in at 240 hours, “Forever” bills itself as the longest film of all time — surpassing the 150-hour “Cinematon,” a seemingly endless collection of vignettes. According to BBC News, “Forever” is being shown “only once” at Helsinki’s IHME Contemporary Art Festival, on an outdoor screen behind the Stora Enso building.

Despite its Olympian length, the film can be summarized in two simple sentences: “Forever” depicts the imagined decay of the aforementioned Enso building, accelerated to the degree that each real-time day equals roughly 700 years. The movie, according to its official synopsis, intends to portray what would happen “if the days of humankind come to an end, and only time and the weather affect the building.”

This is, of course, an absurd abuse of cinema — not so much a film as an endurance test. It’s comforting, then, to hear that the “masterminds” of this project — the Danish art group Superflex — are hardly a bunch of self-serious auteurs. In fact, Superflex is renowned for its elaborate pranks, including a campaign to blanket Copenhagen in red posters that read, “Foreigners please don’t leave us alone with the Danes.”

Of course, impossibly long, self-aware films are hardly novel phenomena: “The Cure for Insomnia” — a movie in which poet Lee Groban reads his 4,080-page piece of the same name, interrupted occasionally by pornographic footage and rock music videos — beat the Danish group to the punch by 24 years. “The Longest Most Meaningless Movie in the World” (1978), a 48-hour montage of advertisements, outtakes and other scraps of found footage, is similarly self-conscious.

Other interminable productions are significantly less tongue-in-cheek. “Cinematon,” for instance, is by no means a joke — or if it is, it’s one director Gerard Courant pursued with remarkable seriousness. A movie at least 31 years in the making, “Cinematon” is a compilation of three-minute, 25-second scenes featuring various subjects doing whatever they want in the allotted time period. Highlights include directors Terry Gilliam eating a 100-Franc note and Samuel Fuller smoking a cigar.

“Matrjoschka,” a German film depicting the glacially slow transformation of a picture, is also quite straight-faced, as is “A Journey of Crude Oil” (2008), a 14-hour Chinese documentary about oil workers in the Gobi Desert.

Whether or not these movies were intended as pranks, they’re all the product of an intriguing cinematic perspective — one in which a film’s value isn’t derived from the experience of viewing it, but from its very existence. Indeed, actually watching these movies would be excruciating and foolhardy. I suspect the directors, although looney in other respects, realize as much. Actual audiences, it’s clear, are an afterthought when pursuing a supposedly unattainable cinematic goal.

That’s not to say it’s impossible to engage these films — merely that movie fans must do so on a purely second-hand basis. Consider a quote from Argentine author Jorge Luis Borges: “The composition of vast books is a laborious and impoverishing extravagance … More reasonable, more inept, more indolent, I have preferred to write notes upon imaginary books.” Like the sprawling, esoteric novels Borges invented and critiqued in his brief short stories, these films can be encapsulated, and admired, in a scant few sentences. It’s best to read about them in newspapers, magazines, blogs — to appreciate their scale without actually having to endure it.