How are sensory details used to provide a vivid depiction of the outside of Mr. Wonka's chocolate factory?

When the narrator provides a description of Charlie's fascination with Mr. Wonka's chocolate factory and describes how the sight of it "tortures" (6) Charlie daily, he also describes the factory. The narrator states that the factory is huge and marvelous, adding, "It had huge iron gates leading in to it, and a high wall surrounding it, and smoke belching from its chimneys, and strange whizzing sounds coming from deep inside it" (6). The narrator goes on to add that for half a mile in every direction from the factory, the air smells of chocolate.