Goes into elaborate detail regarding S'ant Agnese church in Rome, sometimes it feels pedantically so. But it isn't, it's just so dense with information, all of it meaningful and relevant.
You'll learn history, politics, what the parts large and small, the art and detail of Catholic (and sometimes other ) churches symbolize, how things became named, why we do certain things now, and how the small grave of a young girl became a labyrinthine mini cathedral in Rome. I liked reading a small section at a time. Not a Christian, but doesn't matter, endlessly fascinating, excellently researched book. You'll feel like you've been there after reading this book. And/or want to go there.