Tours under Berlin
Day tours of historic locations under the city of Berlin are offered by Berliner Unterwelten (Brunnenstrasse 105, 13355 Berlin, Germany; phone +49 0 30 49 91 04 17).
Among six guided tours are “Dark Worlds,” exploring a bunker from WWII, and “Breaching the Berlin Wall,” looking at tunnels, subways and empty sewers once used by those fleeing East Germany.