LAS VEGAS -- A propeller stops midair. Soldiers packed like sardines on a pier cower in fear of an unseen threat.

Those are the images Christopher Nolan left CinemaCon audiences hanging onto Wednesday as he premiered new footage from "Dunkirk," his long-awaited epic about the storied Second World War evacuation.

"It's something British people grow up with. It's in our DNA," Nolan said. "It's something that's been close to my heart for a long time."

Nolan told the audience of theatre owners that he wanted to tell the story in the most visceral way possible, putting audiences on the beaches, in the air and running with the troops.

The "Interstellar" and "Dark Knight" director shot the film entirely on large format celluloid and said theatres are the only way to experience the suspenseful survival story.

"The only platform I'm interested in talking about is theatrical exhibition," Nolan said. "I want to thank you all for everything you've done for my films. Without you there is no audience."

The film's large eclectic ensemble cast includes veterans like Kenneth Branagh and Mark Ryland, Nolan mainstays Tom Hardy and Cillian Murphy, pop star Harry Styles and a few newcomers like Fionn Whitehead.

It arrives in theatres on July 21.