Cholera has always ranked high among the deadliest diseases to plague mankind. However, it was even more dangerous when doctors and scientists didn't know what caused it or how to prevent its exponential spread. (Image by Wikimedia Commons)
While the people of modern London have their fair share of problems, cholera is not one of them. The disease, however, is far from vanquished, and still exists in other countries. One recent outbreak took place in Haiti and left the country devastated.
The map Dr. John Snow used to track the spread of the disease was fundamental to ending the 1854 cholera epidemic. (Image by mediainstitute.edu)
Dr. John Snow, father of epidemiology (Image by ucla.org)
Reverend Henry Whitehead, curate of the Church of Saint Luke (Image by ucla.edu)