The full trailer for Christopher Nolan's Dunkirk doesn't hold back. Based on the legendary World War II battle, the film depicts Dunkirk in harrowing detail.

"What has happened is a colossal military disaster," says one character (who may in fact be Harry Styles — swoon).

The trailer offers glimpses of Styles, Kenneth Branagh, Cillian Murphy, Mark Rylance, Tom Hardy, and the film's young soldiers, but it's all about the intensity of the battle and the men waiting on that French beach.

Dunkirk opens July 21.