It's hard to overstate what a crucial year 1963 proved to be. The Atlantic's In Focus blogger, Alan Taylor, takes a look back at 50 indelible photos of an indelible year. From the March on Washington to Vietnam. From Beatlemania to the crowning of "America's Junior Miss," 17-year-old Diane Sawyer. And, of course, those searing images from Nov. 22 and the days after, which transfixed a nation and haunted a city.