The 1854 Broad Street cholera epidemic was a severe outbreak of cholera that led to the deaths of 616 people. It was part of a global cholera pandemic that lasted from 1846 to 1860. The outbreak was investigated by the English physician John Snow, who discovered that cholera is caused by contaminated water, rather than by air, as the previous “miasma theory” held. The Broad Street outbreak, which arose on August 31, 1854, was the most severe of several other concurrent outbreaks of cholera in London. Many of the victims of the Broad Street outbreak were taken to Middlesex Hospital, where their care was overseen by the famed nurse and reformer, Florence Nightingale.

Snow historically charted the outbreak to the Broad Street water pump by conducting interviews with the help of Reverend Henry Whitehead. By mapping the results of these interviews, they were able to determine that all of the afflicted had contact with a Broad Street source. The miasma theory was further challenged by the realization that none of the employees of a nearby brewery contracted the disease; they were given a daily allotment of beer, so they were far less likely to drink water from the nearby well.