The evacuation of Dunkirk is one that has had a huge impact on the British.  If not for the evacuation, there’s no guarantee what would have happened if not for Operation Dynamo.

It’s far more than just a British story.

“It was a massive event that still has international significance, says Joshua Levine, author of Forgotten Voices of Dunkirk, and a historical consultant on the film.  “Everything that’s celebrated about World War II—in Britain, in the United States, and all around the world—would not have happened without the Dunkirk evacuation taking place.  It was unbelievably important.  If the British army had been killed or taken prisoner, Britain would almost certainly have surrendered, and we’d likely be living in a very different world today.  To me, Dunkirk is about the preservation of freedom.  Once those ships were underway, the world still had a chance.”

Would anyone want to imagine a world in which Britain surrendered?  How would lives have been changed?

“Your life and mine would have been profoundly changed had that courageous, brave, patient, impossible moment not been lived through by people who stuck at it, and in so doing protected all of our futures,” says actor Kenneth Branagh, who played Commander Bolton.  “Its place in our military, social, political, and emotional history can never be underestimated.  In a sense, you could look at an evacuation as being unheroic, but somehow it adds up to something phenomenally heroic about the human spirit.”

What does Dunkirk mean for the British people?

“It has a deep meaning for the English people,” offers Mark Rylance, who plays Mr. Dawson.  “We were the underdogs on that beach, but we rose to the occasion and eluded the superior forces of the enemy at that time.  The Dunkirk spirit has to do with that perseverance and endurance and also selflessness.”

The Dunkirk spirit is something that resonates with the British.

“The Dunkirk spirit brings to my mind a sense of togetherness and a show of community—coming together to help out someone in trouble,” says Fionn Whitehead, who plays Tommy and is the first person we see on screen.

Because of Dunkirk, “the Dunkirk spirit” is forever a part of the British lexicon.

“It’s something English people pride themselves on: that sort of plucky grit and determination in the face of adversity,” says producer Emma Thomas.

Written and directed by Christopher Nolan, the war film stars Fionn Whitehead, Tom Glynn-Carney, Jack Lowden, Harry Styles, Aneurin Barnard, James D’Arcy and Barry Keoghan, with Kenneth Branagh, Cillian Murphy, Mark Rylance, and Tom Hardy.

Warner Bros. Pictures opened Dunkirk in theaters everywhere on July 21, 2017.  Filmed with both IMAX and 65mm cameras, it’s best recommended to be viewed in 70mm.