Be the Historian!

What Can Maps Tell Us?

Maps do more than represent geography—they can also help solve problems. In this exercise, you will use a 19th-century map to figure out how cholera spread in the city of London. You will see how using a map helped end cholera’s reign as one of the deadliest human diseases in history.


The context: On August 31, 1854, “the most terrible outbreak of cholera which ever occurred in the kingdom” broke out in the Soho neighborhood of London. Soho was a working-class neighborhood with high population density and poor sanitation. Over the next three days, 127 people living around Soho’s Broad Street died. One week later, the death toll reached 500. Authorities did not know how the disease spread or how to prevent further deaths.


The solution to the problem came from a local pharmacist, Dr. John Snow. By plotting the cholera cases on a map of Soho, Dr. Snow figured out how the disease spread. He then convinced the local council to act, ending the deadly outbreak. Without Dr. Snow’s efforts, many more people would have died.

Go to the task