“What has happened is a colossal military disaster.” The solution was code named Operation Dynamo, and it became legend. Things weren’t going well for the pre-U.S. Allied Forces in the spring of 1940, and what almost happened on the beaches and in the harbors of Dunkirk would have been catastrophic. But what did take place was borderline miraculous and led Winston Churchill to deliver his “We shall never surrender” speech.

Here is the full trailer for Dunkirk, writer-director Christopher Nolan’s look at the massive evacuation of 400,000 Belgian, British, Canadian and French troops who were surrounded by the German Army and faced capture or slaughter during the Battle of France.

“They need to send more ships.”

“Every hour, the enemy pushes closer.”

“They’ve activated the civilian boats.” “Civilians? We need destroyers.”

“You’re weekend sailors, not a bloody navy.”

Tom Hardy, Cillian Murphy, Kenneth Branagh and Mark Rylance star in the film, about which Nolan said at CinemaCon: “[It’s] one of the greatest stories of human history. At its heart, it’s a survival story. The enemy is closing in on the British on this beach with no escape. I wanted to put the audience in the story.”

Nolan also produced the film with Emma Thomas, and Warner Bros. will release it July 21. Check out the harrowing trailer above, and tell us what you think.