Opium was at its peak usage in the 1800’s. Opium dens were also established in this time, as sites to buy and sell opium. Dens were commonly found in China, Southeast Asia, the United States, and parts of Europe. Opium dens sprang up in San Francisco's Chinatown and spread eastward to New York. Opium was known to ancient Greek and Roman physicians as a powerful pain reliever. Plus