that's where we'll start off morning with martha teichner. of course, today is st. patrick's day.the world, more than 70 million people have irish roots. pretty impressive when you population of ireland is only about 5 million. conor knighton takes us back to the emerald isle. >> reporter: it feels like everyone is irish on st. patrick's day. 30 million americans actually claim irish ancestry. >> it's such a special experience to tell them something about ancestors that have directly affected them today. >> reporter: coming up on "sunday morning," we pay a visit to epic, the museum of irish emigration in dublin. >>> millions tune in to watch him every night as he hosts "jeopardy!." one of the longest running game shows on television. luke burbank has some questions for the man with all the answers. ken jennings. ♪ >> from the stage --ly. the greatest "jeopardy!" player of all time, and now he hosts the show. but he is hoping you won't hold that against him. >> something about that kind of success seemed not just morally suspect, but unseemly, you know. bad manners to be famous. >>