Segeberger Kalkberg

[1] The gypsum was formed as sulfate evaporite sediments, which were deposited about 250 million years ago by the Zechstein Sea.

Smaller disturbances in the more recent epochs of earth history allowed the less dense Zechstein salts to flow together and force their way upwards from a great depth into the younger overlying rocks to a level near that of the present-day surface.

The red cliffs of Heligoland or the Münsterdorfer Geestinsel are limestone, one of the few formations in Schleswig-Holstein which was not created by the ice ages.

Between 1273 and 1308 Adolphus V the Pomeranian, second-born brother of Count John II the One-Eyed of Holstein-Kiel, resided on the castle.

In 1315 Adolphus VII was slain on Siegburg Castle in his bed by a group of knights led by Hartwig Reventlow personally at feud with him.

In 1397 Holstein-Rendsburg partitioned Holstein-Segeberg again as a secundogeniture with Siegburg Castle as residence, this time for Gerhard VI's younger brother Albert (Albrecht) II.

Before the First World War, the Kalkberg was property of the Prussian state, which every year made considerable profits from the gypsum mining.

After the discovery of the cave, the Prussian Ministry of Trade and Industry agreed to quarry operation with the provision of long-term protection of the town of Bad Segeberg.