Great Grotto, Heidelberg Palace Garden

The entrance to the water features in the Great Grotto is designed as a portal. The wall panels on the sides are decorated with rusticated bands, the gable is broken open. The inner gate pillars rest on a crouching wild boar and a bear and are crowned with two deer. Above the entrance in the gable is a reclining lion. The figures of other animals, such as a wolf, monkey, chamois and fox, as well as two deer that populated the gable field are no longer there.The interior of the grotto is reminiscent of Moorish water features, when a spring splashes over a rocky slope piled up with stones. An opening in the grotto ceiling provides daylight.
Source: landeskunde-online.de/rhein/hd/schloss/bauten/garten/grosse_grotte1.htm

Created 1615-1619 under Elector Friedrich V by Salomon de Caus.

The portal of the Great Grotto alone is worth seeing. The grotto itself is not always open.
The pools in front of it are populated by toads, salamanders, etc. from March to October.