An interest, a passion, an obsession — such is the subject of Titanic, the great, unsinkable ship that went down in April 1912, an occasion whose centennial is keeping enthusiasts busy this year, including the two who will speak at 3:30 p.m. today in the Hall of Christ.

Longtime Chautauquan Steve Piper, whose interest has become his passion, will share his obsession, relating some history and some new findings about the ship and where it lies.

Journalism professor and writer Julie Hedgepeth Williams will discuss her recent book, A Rare Titanic Family: The Caldwells’ Story of Survival, which relates the tragedy though the eyes of her great-uncle Albert Caldwell, who, with his family, through grit and good fortune, was one of the few to survive the ordeal intact.