For all the perils of pounding around the track at heavy speeds, the racers may have the best of it after all: theirs is the only uncrowded space for miles around the Indianapolis Speedway and a driver gets the split-second impression that the nose of his car is parting a sea of people, throwing them back in high waves on each side. This is America's biggest sporting crowd, and through it run moods ranging from fiesta to bloodlust. Small wonder the 500 is the most photographed of all events. As the scenes at right and on the following pages show, the camera is a call to mug, prance a bit or pose pensively, as if to document one's individuality or be lost forever in the throng.