At the turn of the 19th century, cities, municipalities, and economic associations transformed the landscape of the Bergisches Land and Sauerland in a groundbreaking way. In 1889, Professor Dr. Otto Intze from Aachen, an engineer and specialist in hydraulic engineering, constructed the first curved dam for a drinking water reservoir in the Eschbachtal near Remscheid. This pioneering achievement was followed by a wave of dam constructions aimed at harnessing hydropower and providing drinking water, which turned the picturesque hills and mountainous landscape between the Rhine, Ruhr, Sieg, and Diemel into a diverse lake region. By the time of World War I, around 20 dams had been built, and powerful dam constructions continued until the 1980s. Over 192 pages, more than 160 expressive photographs, taken from the air and along tranquil shore paths, capture the atmosphere and character of 41 dams and reservoirs, complemented by texts detailing their construction history.