This circular route opens up the magnificent gypsum karst area of the Sachsenstein.
This has been a nature reserve since 1950, together with the Höllstein, covering 315 hectares. It includes the ponds near Walkenried, beech forests, and meadow areas. The nature reserve contains near-natural stream courses, lowland moor and swamp areas, as well as floodplain forests. On the slopes grows dry limestone slope forest, and on cliffs thrives feather grass grassland. The beech forests have a high proportion of oaks, probably a former use as pasture woodland.
The at least 50 relatively shallow ponds were created in the Middle Ages by monks of the Cistercian monastery Walkenried as fish ponds. They partly originated from older subsidence lakes. The Priorteich, located between Bad Sachsa and Walkenried, is the largest of the ponds in the nature reserve. On its northern shore there is a forest outdoor pool, a supervised bathing lake with catering on site. From the parking lot, the natural swimming pool can be reached after 400 meters.
The Sachsenstein is a mountain made of Werra anhydrite, whose prominent rock spur slopes down to the north, west, and southwest towards the Uffe valley. Here lies the ruin of the Sachsenburg castle, accessible via a side path, built at the instigation of Emperor Henry IV and first mentioned in documents in 1073. The castle was already destroyed again in 1074 and was significantly damaged in 1869 during the breakthrough of the Sachsenstein for the construction of the South Harz railway. The “Zwergenlöcher” are a special feature in the nature reserve, shallow swelling caves that form under water intake during the conversion of anhydrite to gypsum. Their largest was the “Waldschmiede.” It collapsed in 1990; the ruin can be seen on the circular route. From the viewpoint at the castle ruins, there is a view of the railway tracks. The track bed is reinforced with strong rail bundles. The railway embankment continuously sinks over a gully cave at the foot of the steep wall.