This masterclass on Sherlock Holmes explores two of Holmes's city cases. In The Red-Headed League (1891), Holmes explores London both above and below from the pathways behind the 'shabby genteel' square of Jephro Rucastle's pawnshop to the subterranean vaults of the City and Suburban Bank. In "The Man with the Twisted Lip" (1891), Holmes, disguised as an addict, is discovered by Watson in an East End opium den in a story highlighting Victorian social problems of opium use and begging.