MOST DAYS WE APPEAR TO LIVE IN A WORLD gone mad, a time and place in which ignorance of history is treated as a kind of virtuous purity. But sometimes, cosmically, the right movie arrives at just the right time: and right now Christopher Nolan’s Dunkirk feels like a salve. Its visual and sound effects are elaborate and impressive. This is a grand spectacle, not an empty one, a rare example of the Hollywood blockbuster dollar well spent. Dunkirk is extraordinary not just because it’s ambitious and beautifully executed, but because Nolan, who both wrote and directed it, has put so much care into its emotional details—and has asked so much of, and trusted, his actors. As great filmmakers before him—Lewis Milestone, Sam Fuller, Brian De Palma—knew, you can’t tell…