Italian film-maker Michelangelo Frammartino, creator of the subtle and beautiful movie Le Quattro Volte (The Four Times), has returned with his first substantial feature in 12 years. It is effectively another silent movie: a mysterious, wordless evocation of Calabria in southern Italy, notionally set in the early 60s but actually unfolding in something like geological time. The dead-slow, dead-calm Il Buco (The Hole) is similar to Le Quattro Volte in style and substance, and incidentally restates a trope from that film: the ageing, unwell shepherd, played by a nonprofessional, whose craggy face is itself a kind of microcosmic landscape on which the camera lingers in closeup.
But where Le Quattro Volte was populated almost entirely by animals, their lives unhurriedly transcribed by Frammartino’s camera, here we get human visitors from the big city, from Milan in the prosperous north, arriving in Italy’s southwesternmost tip to investigate a cave; the film is inspired by the Piedmont Speleological group who in 1961 pioneered a dangerous descent into the unexplored depths of the Bifurto abyss, 687 metres down, which had to be navigated without the hi-tech kit taken for granted now. Il Buco is the existential opposite of a mountain climb: it is closer to a moon mission – yet the opposite of that too: an inward journey into a dark unknowable world beneath our feet, accessible by a strange hole.
There are heart-stopping scenes in which the young scientists have to set fire to a page ripped from a magazine and drop the flaming paper down into the vertiginous void to get a sense of depth: an inverted rocket launch. Yet the existence of these cave explorers, like that of the landscape and the animals and the shepherd, is rendered by Frammartino without dialogue. We see them mostly murmuring together from far away, as if they are being watched by creatures from another planet, or by the millennia-old spirits of the cave, who have taken up residence in the sky. The film declines to offer up its meaning, or its reason for being, and asks us to think about something outside the passage of time.
• Il Buco is released on 10 June in cinemas.