Where: The Netherlands and EnglandWhen: 1099A combination of high tides and storm waves on the North Sea flooded coastal areas of England and the Netherlands, killing 100,000 people.
Where: United StatesWhen: 1889The Johnstown Flood, in Pennsylvania, was considered one of the worst disasters in U.S. history. After an unusually heavy rainstorm, a dam several miles upriver from Johnstown broke. One out of every 10 people in the path of the flood died, a total of 2,000 people in less than an hour.
Where: ItalyWhen: 1966After a heavy rainfall, the Arno River overflowed, flooding the streets of Florence. Many great works of art in the museums were damaged, as was the architecture of the city. In two days, more than 100 people died and the city was covered with half a million tons of mud, silt, and sewage.
For other floods, see Floods, Avalanches, and Tidal Waves at Infoplease.com.