How does Herman Wouk use imagery in The Winds of War?

Imagery:

"Yes, here the Germans sit at the heart of Europe, Henry, these perplexing first cousins of ours, simmering and grumbling away, and every now and then they spill over in all directions, with a hideous roar. Out they pour from these lovely little towns, these fairy-tale landscapes, these clean handsome cities—wait till you see Cologne, Nuremberg, Munich, even Berlin and Hamburg—out they bubble, I say, these polite blue-eyed music lovers, ravening for blood. It gets a bit unnerving. And now here's Hitler, brining them to a boil again."