The Mantahl near Percha, close to Lake Starnberg, is a landscape depression that was geologically formed by the Isar-Loisach glacier during the last ice age. Lake Starnberg itself was formed as a tongue basin lake, and the Mantahl was formed by the movements of glacial water and deposited moraine material.
The name "Mantahl" could come from old field names, but its exact origin is unclear. The region was already settled in Roman times, as trade routes ran along the lake. In the Middle Ages, the area was used by local noble families and monasteries, especially for agricultural purposes such as livestock farming and arable farming. The valley's location provided protection from the weather and it was a fertile area.
Today, the Mantahl is still used for agriculture, but is also important as a local recreation area. Hiking and cycling trails lead through the picturesque landscape, which is characterized by its hilly topography and views of Lake Starnberg. The region around Percha, including the Mantahl, has retained its rural character despite its proximity to Munich and is a popular place for nature lovers and day trippers.