When John Snow, started training as a doctor the cholera outbreak killed 300+ people
Ten plus years has pass , John Snow was working as a very successful doctor at London.
In the 1855, cholera have killed 700 people in a small town called Soho.
Dr Snow, plot on map where all victim was and he found out that all of the victims get there water from the same pump in Broad Street. Those who didn't get cholera gets there water from other water pumps
The water pump is remove ! Now we need to get water from a further pump.
Dr Snow, thinks that something might be wrong with the water pump near Broad Street. So, he got the permission to remove the water pump.
Dr Snow, proved that cholera wasn't pass through air it was pass through water.