Beside the mines there are also some other artificial cavities, which we examine occasionally. To this objects belong bunkers, factories, tunnels and channels with their appendant cellars and access tunnels.
Since there are not so many interesting objects, our work is limited so far only to a few objects.

Basically you can apply the same principles as described in the mining, particularly since many bunkers were created in old mines.

Old supplying channels are interesting due to their interlace structure and are often the only possibility of attaining access to forgotten systems and cellars.
Newer systems are created often parallel or in direct proximity to the historical ones, so that surprising branchings or transitions to residues of historical cellars and factories are not rare.
Suddenly you will find yourself in relics of the start of the 19. Century, in which the time seems to have stopped.

The old bunkers inspire the fantasy of many humans. Therefore these are mostly well secured, if they were not destroyed after the war.