Ermmmmmm, I would go for something that the interviewers will know little or nothing about. This will not only stir their interest but will save them asking questions about a subject they know more about.
The chances they know nothing about leper colonies is fairly remote however, and it sounds more interesting than local history.
How about the history of vampires, where FACT meets FICTION??? That was the best presentation I have ever seen. The interviewee did not come accross as Goth-nerd, and I was thouroughly absorbed in it.
Whatever you do, remember death by power point is a painful death, so opt for free speech, visual aids and humour. Powerpoint should only be there for aide memoir of very, very pertinent points.
Good luck.