THE ISTER

*** (three stars)

Running time: 189 minutes. Not rated (mature subject matter). At the Anthology Film Archives, Second Avenue and Second Street.

JUST because “The Ister” gets three stars doesn’t mean you should run right out to see it.

Perhaps you’re more the type who’d like to spend $10.75 for the privilege of sitting through mind-numbing commercials and trailers, followed by Hollywood crap like, say, “The Pink Panther.”

Or maybe you’d get more pleasure out of going to the commercial-less Anthology Film Archives for “The Ister,” a stimulating, 189-minute meditation on the Danube River.

The directors, David Barison and Daniel Ross, take their inspiration from 1942 lectures by Martin Heidegger, one of the last century’s most influential and controversial philosophers, on Friedrich Holderlin’s poem “The Ister” (the waterway’s ancient Greek name).

Traveling the length of the Danube, from Romania to Germany, “The Ister” allows some of today’s leading minds to ruminate about the state of modern civilization.

At over three hours, “The Ister” is challenging – and then some. But what’s wrong with challenging?

So if “The Ister” sounds like something you can wrap your brain around, catch it during its run through Thursday.

vincent.musetto@nypost.com