Concentration Camp

I'm sure that other people have a already alluded to all of the atrocities that the Nazi's committed in both the fort and the ghetto area.  But I found it interesting that the fort was originally used by the Austrian empire to hold political prisoners and prisoners from there own wars. Included in this was the tunnels that we all went through that, which we all went about 500 m, however there was a total of over 30 km of tunnels around the fort itself.  It just seems remarkable to me how long of tunnels they could have created for just this single fort way back before they had modern technology of today.  Whether or not they used slaves, paid workers, or both I do not know; but no matter the workforce, it must have taken years!  Going back to the Germans, this camp was luckily not as deadly or devastating, though there was still much death, as say Auschwitz, going through both the prison and the museum afterword, one can tell just how much these camps drained the lives from people, both the ones who were confined and the ones who were not.