Opium dens became a much mythologised world, where aristocrats could stumble in and discover a cornucopia of vice.

BBC: 100 years of the war on drugs

Together these interlopers built their own cities within the city, block after block of gambling parlors and opium dens and brothels where inmates dangled bare breasts from windows and did unspeakable things with animals.

NPR: Elevating the World's Oldest Profession in Chicago