The world's great cities have long been a focal point for artists, writers, poets, and social commentators, who have sought to use them both as backdrop or canvas for their work and as the subject matter of commentary and critique about the condition of society. Some have cast cities as places of nightmares and dystopian visions and landscapes. The French writer Octave Mir-beau evokes this genre when he notes that the dirt and smog of nineteenth-century London are part of “a dream, of mystery … of chaos,” what he refers to as the “special nature of the prodigious city” (qtd. in Ackroyd 773). Others, such as the Romantic poets, described the city as antinaturalistic, a place of nature's expulsion. Here urban dirt and pollution were metaphors for the degradation of human spirit and character; the English novelist George Gissing, for instance, characterized the smells in the district of Southwark in London as rising like “a miasma that caught the breath.”