BOSTON — On Boylston Street, crowds gathered to stare in disbelief at a city that may never be the same.
An armored personnel carrier idled on a nearby street corner and armed National Guard troops flanked the sidewalks. The police barricades marked a 12-block crime scene. Makeshift vigils of flowers and heartfelt messages of prayer and remembrance were clustered here and there. And the sound of birds chirping on a glorious spring day seemed incongruous for a city so stunned it was as if the blast was still ringing in its collective ears.