With COVID-19 the most recent reminder, pandemics have plagued humankind for much of recorded history. Cholera killed millions around the world in the 19th century, and there were three major cholera epidemics in the United Kingdom. Like modern data scientists in medical fields, 19th-century proponents of data science used data and visualizations to investigate the causes of cholera, suggest prevention strategies, and argue for better sanitation. While some of these endeavors were based on misguided beliefs current in the medical and scientific community at the time, others debunked misconceptions and saved lives. This case follows William Farr, John Snow, and Florence Nightingale, three early data scientists, as they created their data visualizations, which had different persuasive effects on their contemporaries. It is accompanied by a student spreadsheet with the data they used, as well as a handout with a data visualization exercise. This case is used at Darden in the second-year course, “Storytelling with Data,” and it would also be suitable in courses covering data visualization or persuasion.