Every evening at 7, Joseph Vitolo walks out the backdoor of his boyhood home in the Bronx and ascends a long stairway to a shrine that overlooks the northern tip of the Grand Concourse. He then leads the few people who have gathered in the recitation of the rosary. On some nights, no one shows up and he performs the service alone. Other nights, Mr. Vitolo is himself absent, having fallen asleep in front of the television set or lost track of the time. Mr. Vitolo, a slow-moving 66-year-old with a gravelly voice and sandy hair flecked with gray, has sought to carry out this nightly act of devotion since Oct. 29, 1945. That is when, at 9, he said he witnessed the Virgin Mary hovering over the spot where the shrine is now. The sighting catapulted Mr. Vitolo, a child of Italian immigrants, to news media celebrity. Spurred by extensive newspaper coverage, more than 30,000 people eventually crowded the spot, just south of Van Cortlandt Park, hoping to be touched by the heavenly presence that, it was said, had been communicated to the child.