The Foundation for Water and Energy Education offers this informative guide to hydroelectric power. To begin with, users can tour a hydroelectric dam by clicking on successive systems shown in a diagram. This part of the guide is somewhat lacking in content, as it is mainly illustrations with little explanation. However, the rest of the guide is more illuminating. Other sections show users how dams can accommodate fish, and a more specific description of a hydropower generator is also available. One of the best resources is the timeline, which charts many of the most important developments in hydropower since 500 BC. [CL]