The Broad Street cholera outbreak of 1854 helped demonstrate that cholera was spread by contaminated water. By talking with residents and studying the spread of cholera cases, Dr John Snow was able to pinpoint the water pump that was the source of the outbreak. He disabled the pump by removing its handle, which is popularly reported as ending the outbreak.
The above image was created by Dr Snow. It shows the clusters of cholera cases, which are represented by the black rectangles on each street. Which of the water pumps is the pump that was identified by Dr John Snow?
Image credit: Wikipedia