Just to the South of Osterode lie some white Cliffs. They are actually quite beautiful to look at.
Those Cliffs are an outcrop of Anhydride and Gypsum, both of which are also mined in the Area.

Back in the Day, the Gypsum Mines were way more economically significant than they are now, but there are still a few Companies operating here in Osterode.
And the Gypsum they mine is used for pretty much anything from Drywall to Dental Fixtures.

As with anything here in Germany, those Gypsum Cliffs where used by the Nazis of the Third Reich to aid in their War Efforts. After allied bombings started to intensify, it was planned to move the Production of synthetic Fuels in Tunnels dug into the Rock.
The progress of the War, and the fact that the Dachs IV project was only started in 1944 meant that the Project was never finished. Sadly, many People still dies in the specifically built Außenlager, part of the KZ Mittelbau Dora in Nordhausen, and Death Marches conducted towards the End of the War. That part of German History really is something to be ashamed about. And I say that as a German.

Nowadays, the Gypsum Cliffs are luckily just a beautiful sight to behold and also still an Economic Powerhouse in the Region, along some Plastics and Metal Manufacturing.
And they are also quite crumbly indeed.