On the seaside promenade at Redcar, a depressed beach town on England’s northeast coast, 1,500 period-costumed local extras helped re-create the WWII evacuation at Dunkirk, France. To complete the scene, production designer Sarah Greenwood coordinated the maze of fully dressed facades topped by burnt-out buildings, trained circus horses, a massive barge, a Ferris wheel, a bandstand and vintage vehicles through which a dazed James McAvoy wanders, reacting to the chaos and despair of England’s army driven to the sea.

In depicting the historic retreat, director Joe Wright hoped to capture as much energy and humanity as possible. The “hugely expensive, $4 million shot” (per producer Paul Webster) might have been a logistical nightmare, requiring two months of prep and two weeks of build-out, but it also solved all continuity problems, Greenwood points out. The crew had to fight against both the tide and the setting sun. “We were so lucky. It was the best time of day to shoot,” Greenwood notes. “We had a perfect milky sky. The only CGI effects were extra smoke in the sky and extra men in the sea. Everything else was on the beach.”