In the location's words:

The Waidsee, a former quarry pond west of Weinheim in the Rhine-Neckar district, was created between 1966 and 1977 during the construction of the highway between Darmstadt and Heidelberg. The lake is around 700m long, 500m wide and up to 20m deep, making it ideal for diving. Water sports enthusiasts, anglers, divers and swimmers will find numerous recreational opportunities here. There is a public lido, a sailing club and a diving school with a training platform and underwater tanks.