In your opinion what is the next greatest Ken Follett book?

I had never read The Pillars of the Earth and saw
on this website that several people said it was one
of their most favorite books. Now I know why as I
have just finished it and cannot think of anything else
for days it was that great. Of course now I want to read
another of his novels and I am hoping I can get some
response on which is his next best book!