To discover hidden treasures in an area you must spend some time there. If you are an explorer type - just do that in the Nordhausen region. I always try to do that too.
Find some of the castles which even offer accommodation. Just stop at a tourist information and ask. We will not any longer provide free advertising for individual businesses.
During my next visit to Thuringia, I want to find out more about all the activities which were going on in this state during WW II with respect to the production of high tech weapons using slave workers from concentration camps to build the underground facilities and to work later there in production.
Their also still tales about treasures hidden by the Nazis. We offer the only English book - which we know - about some of this past and which is published in Germany.
On of the concentrations camps which supplied slave workers for the war machinery was called "Dora" and located in the Nordhausen area.
Today, a memorial is dedicated to this dark part of Germany's past and in the hope that no other nation will do something similar again. Unfortunately, this task could not be achieved.

The official name of the memorial is "KZ-Gedenkstätte Mittelbau-Dora".
I did not visit it because it is only one fragment in my planned overview about the activities which were going on in the "Jonastal" during the Hitler regime. I want at least inform myself first before I write about this time and find links to trustful English web sites.