Dunkirk may not have the resonance for Americans as the Battle of the Bulge, but Christopher Nolan's new film may change that. In it, Mark Rylance plays Mr. Dawson, one of the many boatmen who played such a pivotal role in early WWII. The film tells the harrowing story of how Allied Troops tried to evacuate the beaches of Dunkirk, France while taking heavy fire from enemy forces. "Dunkirk" opens wide on July 21.