Zemeckis turns the event into a kind of blockbuster Cinéma Pur – an almost avant-garde game of composition, movement and perspective, exhilaratingly attuned to form and space. ("Mad Max": Fury Road did the same.) The camerawork is subtle and meticulous, the 3D head-spinningly well-applied.

Almost magically, The Walk transforms itself into a beguiling caper movie, full of comic energy and nimble ingenuity.

What Zemeckis delivers here is an entirely different brand of spectacle from that which audiences have come to expect from recent studio tentpoles, sharing a true story so incredible it literally must be seen to be believed, as opposed to imaginary feats full of impossible CG creatures.

When you're watching something Zemeckis made, anything can happen, and reality is up for grabs. In this case, he's used his powers for good, and the end result is stirring and spectacular at times, with a devastating, if subtle, final line of dialogue.

Zemeckis reminds us that it’s in the service of reality, rather than fantasy, that digital technology is often most potent.