Half a day. The mysterious dark world, which exists below Berlin's surface, is full of surprises. No one will ever know how many tunnels, canals, brewery store rooms and shafts are hidden under ground. Do not miss the opportunity to come along on an adventure to some of Berlin's historic spots below ground. What was it like for a soldier to hide here during World War II? Is there something below the Schlossplatz? What does Adolf Hitler's airport look like behind its fronts?