Booze tunnel in Helsinki... not from prohibition times but built between Alko's factory and warehouse. Decommissioned, now as a reserve shelter. The tunnel is underneath the Ruoholahti mall, in floor -6... deep under everything else. So deep that it is even underneath the kid amusement park Hoplop in floor -5 :-)
Tero happened to notice that this was open for public tour today and sent me a note. Thanks!