In Naples, Italy, the past isn’t relegated to what’s behind us. In its crumbled, ancient majesty, the past is quite visible. And when it comes to the legacy of Mount Vesuvius — able to change the sky and move the earth — history encompasses all that’s above and plenty that’s subterranean, too.

The notion of Naples as a place in perpetual contact with its ghostly, grand history, whether you’re a citizen living on top of it or a visitor passing through, is what gives Gianfranco Rosi’s patient, eccentric documentary “Pompei: Below the Clouds” its strangely beautiful atmosphere of reflection and restlessness. Like a cagey docent who would rather guide your attention than talk your ear off, Rosi (“Fire at Sea”) trusts your own curiosity, in turn bringing thoughtful life to this city portrait of people and places.

The result — from the tunnels carved out by tomb robbers to the trains that run day and night — is a cinematic gift for the senses and specifically, to paraphrase one of the more philosophical characters, about our understanding of time’s ability to both preserve and destroy.

Shot in richly textured black and white with a fixed camera, Rosi makes the region’s present look as if it’s always teetering on the edge of a haunting archival status. He returns often to an empty, dilapidated cinema projecting the past (snatches of the silent “The Last Days of Pompeii,” Rossellini’s “Journey to Italy” and older documentaries) as if seeking kinship with earlier chroniclers. And maybe to gently remind us that moviegoing is as endangered by shifting sensibilities as are people who live in the shadow of a volcano, one whose AD 79 eruption is a civilizational marker nobody there can truly escape.

The company Rosi seeks out all seem to be stewards of that connection, whether to the weight of history or each other. There’s the lab-coated museum curator who treats statues in underground storage as dignified friends worth revisiting. A Japanese archaeological crew amid ruins and scaffolding is eager to meet undiscovered victims of Pompeii’s devastation. Even the prosecutor touring a buried villa that’s become a crime scene, illegally stripped of its frescoes, bemoans what’s been lost when thieves rob a people of their ancestors’ memories.

Meanwhile, dedicated fire department operators answer every Neapolitan’s phoned-in worry, primarily about the threat posed by their biggest, oldest neighbor, whose every belch of smoke and gas (a favorite insert shot of Rosi’s) is its own warning that time is precious. To the Syrian sailors transporting grain from Odessa, however, docking in Naples is a respite compared to the danger in their homeland and the war in Ukraine. For abiding calm and a belief in the future, there are drop-ins with veteran teacher Titti — the movie’s most endearing figure — who runs an after-school tutoring center for local schoolchildren.

There’s an intimate breadth to the warp, woof and weave of “Pompei: Below the Clouds,” which is masterfully edited by Fabrizio Federico and boasts an enveloping score by “The Brutalist” Oscar winner Daniel Blumberg. Just don’t expect to know Naples by the end. Rosi’s artistry grasps the limitations of being a long-term guest, visually juxtaposing the ancient and elemental, busts and people. Absorbing this well-chosen album is a treat, and a chance to appreciate the delicate mortality that thrives in a place simultaneously enormous, eternal and ephemeral.