The Grottenfels (I) contains a man-made "grotto" of three chambers connected by passages.
Above the entrance to the main chamber is a carving that unlike the others here is not a bas-relief, but simply a cut in the stone in the form of what appears to be a winged creature.
It appears to have been intended to receive a relief made from some other material and then set into the stone.
The main chamber is 11 m by 3.5 m with a ceiling height of 2.5 m. The side chamber has the same height but is 2 m by 5 m. In the main chamber is an inscription dated to 1115, indicating that an altar was consecrated here.
The third room is the so-called Kuppelgrotte is reached from the main chamber and via a small passage from the outside.
This room is quite narrow compared to the other two and, with its domed ceiling, has a more cavelike appearance.
Next to the external entrance, in an alcove, is another relief, much eroded.
It shows a standing figure, holding a sash in the left and a key in the right hand.
This has been interpreted as a depiction of St Peter.

The outside of rock I also features the Kreuzabnahmerelief (showing Christ's Descent from the Cross).

Below the side chamber, next to the pond, is the so-called Sargstein (tomb stone).
An arched alcove with an open stone sarcophagus at the bottom has been cut into the sandstone.
This is a type of structure known as an Arcosolium.
On top of this rock is a platform reached by an uneven stairway.

The top of rock Ia has been turned into a platform and is reached by a stone stairway that begins between rocks I and II.
A rectangular chamber has been cut into the peak of rock II, known as the Höhenkammer (high chamber).
It can be reached by a stair in rock III and a wooden construction linking rocks II and II.
The platform seems to have been reduced from its original size by rockfalls.
The chamber shows signs of wooden pegs that likely once supported wooden walls and/or a wooden ceiling.
At the east of the Höhenkammer is an apse with a circular window and an altar.
Towards the west is an alcove with columns carved into the rock.
To the north there are pilasters and arched windows.
The northwestern end is marked by the carving of a bearded man (likely dating from the Renaissance or Baroque).
Remains indicate the past presence of further stairways on the rock.

Finally, rock IV has been decorated with the coat of arms of the Counts of Lippe.
The Grottenfels (I) contains a man-made "grotto" of three chambers connected by passages. Above the entrance to the main chamber is a carving that unlike the others here is not a bas-relief, but simply a cut in the stone in the form of what appears to be a winged creature. It appears to have been intended to receive a relief made from some other material and then set into the stone. The main chamber is 11 m by 3.5 m with a ceiling height of 2.5 m. The side chamber has the same height but is 2 m by 5 m. In the main chamber is an inscription dated to 1115, indicating that an altar was consecrated here. The third room is the so-called Kuppelgrotte is reached from the main chamber and via a small passage from the outside. This room is quite narrow compared to the other two and, with its domed ceiling, has a more cavelike appearance. Next to the external entrance, in an alcove, is another relief, much eroded. It shows a standing figure, holding a sash in the left and a key in the right hand. This has been interpreted as a depiction of St Peter.
The outside of rock I also features the Kreuzabnahmerelief (showing Christ's Descent from the Cross).
Below the side chamber, next to the pond, is the so-called Sargstein (tomb stone). An arched alcove with an open stone sarcophagus at the bottom has been cut into the sandstone. This is a type of structure known as an Arcosolium. On top of this rock is a platform reached by an uneven stairway.
The top of rock Ia has been turned into a platform and is reached by a stone stairway that begins between rocks I and II. A rectangular chamber has been cut into the peak of rock II, known as the Höhenkammer (high chamber). It can be reached by a stair in rock III and a wooden construction linking rocks II and II. The platform seems to have been reduced from its original size by rockfalls. The chamber shows signs of wooden pegs that likely once supported wooden walls and/or a wooden ceiling. At the east of the Höhenkammer is an apse with a circular window and an altar. Towards the west is an alcove with columns carved into the rock. To the north there are pilasters and arched windows. The northwestern end is marked by the carving of a bearded man (likely dating from the Renaissance or Baroque). Remains indicate the past presence of further stairways on the rock.
Finally, rock IV has been decorated with the coat of arms of the Counts of Lippe.
Externsteine