Lake Kalksee is named after its limestone deposits that are unusual for the region. The elongated lake is two kilometres long and up to ten metres deep. Citizens of Berlin in particular, have been aware of the lake with its clear water since the early 20th century: A big lido was established on the eastern lake shore.
The bathing area at Lake Kalksee is located at the northern tip of the lake. Water enthusiasts can enjoy a spacious, plain sunbathing lawn with big shady trees. The bathing area is situated between the Woltersdorf lock and the museum park in Rüdersdorf, making it ideal for a quick dip in the cool water on a day of sightseeing. Lake Kalksee was first awarded the blue EU flag for clean water in 2002. An access road takes visitors directly to the bathing area.