In what ways does the setting help portray several themes, motifs, and symbols present in the book Dracula?

The city of London is an important symbol, representing the hub or center of the world in the 1890s. At that time, England was the world's superpower, with an empire on which "the sun never set." London is the crowded, highly populated capital of England and, as the novel illustrates, a center of trade and activity, with ships coming into and out of the Thames at all times. It was a fitting place for the "disease" of the vampire Dracula and his followers to infect the rest of the world. Dracula, fought by doctors and scientists, is able to take on the form of disease-carrying rats and bats. He is very much shown as a sleeping, medieval illness or evil like the bubonic plague. The heroes fight him from modern England using state-of the-art technology, such as blood transfusions.
Dracula's castle at the beginning of the novel—remote, imprisoning, and medieval—is strongly associated with Dracula and symbolizes him as an evil from another age, come to infest the modern world.