Down, down, down, into the Berliner Unterwelt! Photo (cc) flickr user escpeapalumni

The meeting place was normal enough; if I hadn’t known what was going on beneath us and where we would spend the next hour and a half, I never would have guessed at what was just below the ground on which I stood.  Berlin’s Gesundbrunnen metro stop, both inside and outside, lacked the kind of dank, enthralling mystery that was waiting several stories beneath us in the Berliner Unterwelten.