In a new featurette, Dunkirk director Christopher Nolan and his very game cast and crew battle the elements while doing location shooting for this summer’s ultra-realistic World War II action movie. In his quest for realism, Nolan elected to shoot his film recreation of the pivotal events at Dunkirk on the real locations, despite the severe tides and sometimes harsh weather conditions.

Dunkirk tells the real life story of what happened when in the early stages of WWII, 400,000 British and Allied troops found themselves trapped on the beaches of the French coast, pinned down by German fire and unable to escape. A massive rescue effort was mounted, employing naval and civilian ships and aircraft of the RAF to hold off the Germans and evacuate the men across the English Channel to safety. Nolan’s film tells three parallel stories covering the action at sea, on the beaches and in the air.

In a new Dunkirk featurette from Warner Bros. Pictures entitled “Weathering the Storm,” director Nolan, cinematographer Hoyte van Hoytema, producer Emma Thomas and actors Kenneth Branagh and Fionn Whitehead discuss the challenges they faced shooting the movie outdoors on the beaches of France with the wind and the tides battering themselves, their equipment and their sets. Thomas and executive producer Jake Myers reveal that conditions became so brutal, they were forced to rebuild their sets on more than one occasion, and had to shoot around the constant re-construction.

A lot of directors might have been deterred by having to shoot in such unfavorable conditions, but Nolan instead saw the situation as an opportunity to bring another layer of realism to his film. In the featurette we see Nolan and his cast and crew literally weathering the storm in order to capture shots of waves battering the breakwater (or mole) where soldiers are standing huddled together. As star Kenneth Branagh puts it:

That’s very much the Nolan way. We’re out here and we’re out here to work. We’re out here to sort of live it a bit more.

Nolan’s intention with Dunkirk is to allow audiences to live the action as intensely and fully as possible, which is why his movie is shorter and more focused than many of his other films. Early reviews of Dunkirk suggest that all the hard work was worth it, with many reviewers praising Nolan’s stripped-down, almost silent-movie approach to storytelling. In order to give audiences the most authentic and gripping experience possible, Dunkirk is being rolled out on 70MM IMAX in many markets.