PBS
Pbs: Building Big: Dams
A collection of resources about dams that includes basic facts about dams, challenges faced by dam builders, famous dams from around the world, and a lab that helps you understand different kinds of shapes used to construct dams. Also...
Library of Congress
Loc: America's Story: Johnstown Flood
Read about the terrible destruction caused by the Johnstown Flood in May 1889.
Pennsylvania Historical and Museum Comission
Explore Pa History: Johnstown Flood
Examine this historical account of the Johnstown Flood and how it impacted Pennsylvania's history.