They start by underwater earthquakes then the tides start to become very rough and causes a tsunami
Answer:
Here's what I get
Explanation:
John Snow mapped the cholera cases, representing each death as a bar.
His maps showed that many cases were clustered around a public water pump on Broad St. that was close to an old cesspit. The local council eventually disabled the pump by removing its handle.
The diagram below shows his original map overlaid by modern data points. The blue arrow points to the location of the pump.