Winston Churchill one refereed to the former Soviet Union as an enigma, wrapped in "a riddle, surrounded by mystery." Much the same might be said about the Vatican.  A large bureaucracy, competing political interests, the potential and reality of scandal and cover up.

John Thavis, has spent almost 30 years covering the Vatican. He walked the hallowed halls, was one of the "boys on the bus" on the papal plane and understands both the human and spiritual side of this seemingly monolithic and often flawed institution.

Now free of daily reporting, he allows himself to look back in The Vatican Diaries: A Behind-the-Scenes Look at the Power, Personalities, and Politics at the Heart of the Catholic Church.

My conversation with John Thavis: