>> WALK ANYWHERE IN TODAY'S BERLIN, AND REMAINS OF NAZI GERMANY ARE JUST BENEATH YOUR FEET. BERLIN WAS THE BATTLEFIELD OF THE 20th CENTURY. AND TODAY, SEALED UP AND ARE THE SECRETS OF THIS CITY'S DARK PAST. FROM THE MEGALOMANIACAL VISIONS OF THE MADMAN BURIED BENEATH TO HIS DREAMWORLD. HIS GERMANIA THAT WOULD'VE LASTED 1,000 YEARS. AND THIS IS THE LAST LINK TO ...TO A BOMBPROOF SUBTERRANEAN MODERN METRO. YOU CAN HEAR THIS NOW, RIGHT? YOU CAN HEAR THE METRO. IT'S A TIME CAPSULE OF TERROR... >> THIS IS A WEAPON. >> THIS IS A WEAPON? ...THAT, BELIEVE IT OR NOT, ALL STARTED INNOCENTLY WITH BEER. LOOK AT THE SIZE OF THESE. THESE ALL WOULD'VE BEEN FILLED WITH BEER, RIGHT? I'VE BEEN GIVEN SPECIAL ACCESS INTO BERLIN'S SEALED-OFF WORLD UP ABOVE DOESN'T CRUMBLE IF YOU NEVER SEE ME AGAIN, TELL MY MOM I LOVE HER. WE'RE PEELING BACK THE LAYERS OF TIME TO UNCOVER HITLER'S UNDERGROUND LAIR... BERLIN. --<font color="#FFFF00"> Captions by VITAC --</font><font color="#00FFFF">
www.vitac.com</font> HOME TO 3.4 MILLION PEOPLE, BERLIN IS GERMANY'S CAPITAL CITY. IT'S YOUNG BY EUROPEAN STANDARDS, BUT IN ITS 700-YEAR HISTORY, BERLIN HAS GONE THAN ALMOST ANY OTHER CAPITAL CITY IN THE WORLD. BUT IT WAS THE EVENTS OF THE 20th CENTURY THAT LEFT THE DEEPEST MARK. WALK AROUND THE CITY, AND THE UNRECOGNIZABLE. BUT IT'S STILL THERE, AND IT'S CLOSER THAN YOU THINK. >> I'M ERIC GELLER. I'M IN BERLIN, GERMANY -- GROUND ZERO FOR SOME OF THE GREATEST FROM THE DESTRUCTIVE REIGN OF THE NAZIS TO THE FEAR INSPIRED BY THE BERLIN WALL, IT'S A CITY FULL OF DARK SECRETS. AND YET, MUCH OF BERLIN'S EXPLORED UNTIL NOW. >> WE'LL PEEL BACK THE STREETS GREATEST EXAMPLES OF WARTIME WE'LL GO BENEATH THE MODERN SKYSCRAPERS, BELOW THE METRO LINES, AND INTO THE OFF-LIMIT AND ABANDONED NERVE CENTERS OF ONE OF THE MOST SECRETIVE AND BRUTAL REGIMES OF THE WESTERN WORLD -- THE NAZIS. >> MR. SASCHA,<i> GUTEN TAG.</i> >> HELLO, ERIC. >> THANK YOU FOR HELPING ME OUT >> SASCHA KEIL IS A MEMBER OF THE BERLIN UNDERWORLDS' ASSOCIATION. THE GROUP WAS FOUNDED IN 1997, JUST EIGHT YEARS AFTER THE FALL AND SASCHA AND HIS GROUP WERE MY KEY TO GETTING UNDERGROUND. FOR YOU THAT BERLIN AND THE WORLD SEES THIS SECRET? >> BECAUSE IT'S A TIME CAPSULE FOR THE BERLIN HISTORY, AND WE ALWAYS CAN LEARN FROM OUR HISTORY. IF YOU DON'T KNOW IT, YOU ARE DAMNED TO REPEAT IT. >> SASCHA AND HIS GROUP HAVE BEEN THE FIRST TO SET FOOT IN MANY FORGOTTEN NAZI AND COMMUNIST SITES, SEALED OFF BENEATH THE STREETS. IN THE PAST 10 YEARS, THEY'VE FOUND A GERMAN TRUCK BURIED IN GROUND, LOADED WEAPONS, EVEN INSTALLATIONS OF THE WARSAW PACT, FROZEN IN TIME IN THE UNDERGROUND LAIR OF THE NAZIS, A HIDDEN WORLD THAT, FOR 70 YEARS, HAS MANAGED TO SUPPORT THE TONS OF INCREASING FROM THE GROWING CITY UP ABOVE. I WOULD MEET UP WITH SASCHA AND THE BERLIN UNDERWORLDS' ASSOCIATION LATER. BUT FIRST, I WANTED TO DO SOME EXPLORING ON MY OWN. TODAY THE STREET WAS LINED WITH APARTMENTS, BUT MORE THAN 60 YEARS AGO, IT WAS THE NERVE CENTER OF THE NAZI PARTY. HITLER'S CHANCELLERY, GOEBBELS' PROPAGANDA MINISTRY, AND THE FOREIGN MINISTRY OF THE REICH ALL STOOD HERE, BEFORE THEY WERE DESTROYED BY ALLIED BOMBS IN THE WAR. ENTIRE BUNKER CITIES WITH ROADS BUILDINGS. TODAY, LIKE THE BUILDINGS THEMSELVES, MOST OF THE BUNKERS ARE DESTROYED. BUT THERE WAS ONE NAZI BUILDING STILL STANDING. IT WAS THE TRAFFIC MINISTRY OF THE TRAFFIC MINISTRY WAS BEST-KNOWN FOR BUILDING TODAY THE BUILDING WAS ABANDONED AND FULL OF BULLET HOLES. BUT I FOUND A WAY INTO ITS BACK COURTYARD TO SEE IF I COULD FIND EXISTENCE OF A LOST BUNKER. >> ALL AROUND US IS WHAT EAST BERLIN. THIS WAS IT. THIS WAS WORLD WAR II. ALL THOSE HOLES ARE THE STRIFE FROM BULLETS. HUNDREDS OF WORKERS ONCE FILLED THE TRAFFIC MINISTRY. IT WOULD'VE BEEN ONE OF THE ALLIED FORCES' BIGGEST TARGETS. THAT MEANS THERE WAS NO DOUBT THAT THERE WOULD'VE BEEN A BUNKER ON THE PREMISES IN CASE THIS LOOKS LIKE THE ENTRY TO A BUNKER. THIS IS NOT OPEN TO THE PUBLIC. IF YOU LOOK AT THE CONDITIONS, CAVE IN. I'M GONNA DO DOWN HERE. I'M GONNA SLOWLY DESCEND. I'M WALKING KIND OF GINGERLY BECAUSE, AGAIN, I CAN'T TELL -- AND I CAN SEE CHAMBERS FROM RIGHT HERE. THIS IS A CORRIDOR THAT LEADS TO ANOTHER SERIES OF BUNKERS. I WAS MORE THAN 15 FEET BENEATH THE COURTYARD OF THE TRAFFIC MINISTRY AND JUST OVER 150 YARDS FROM WHERE THE NOW-DESTROYED FUHRER BUNKER ONCE SAT, THE VERY SITE WHERE HITLER AND HIS WIFE, EVA BRAUN, TOOK THEIR LIVES. WHILE THEY ARE LOCATED NEAR EACH OTHER, THERE IS NO EVIDENCE THAT THE TRAFFIC WOULD'VE BEEN CONNECTED. TUNNELS CONNECTING THIS BUNKER TO THE SUBWAY AND AIRPORT. CRUMBLING WALLS PREVENTED ME FROM FINDING THESE SUBTERRANEAN ESCAPE ROUTES. AND THIS IS THE JEWEL THAT I WOULD LIKE TO GO INTO, BUT I DON'T KNOW IF I CAN. APPEARS TO BE SOME LABYRINTH OF ROOMS. BUT THIS IS STOPPING ME FROM GOING IN THERE. AND THAT'S STOPPING ME FROM GOING IN THERE. SO I GUESS, UH, I'M GOING IN THERE. IF YOU NEVER SEE ME AGAIN, TELL MY MOM I LOVE HER. [ GRUNTS ] IT LOOKS LIKE THERE MIGHT HAVE BEEN A TOILET RIGHT HERE. THERE'S OVENS RIGHT HERE. RIGHT? IN SOME OF THESE PLACES, THERE WOULD'VE BEEN KITCHENS. THERE WERE REMNANTS OF KITCHENS, VENTILATION, PLUMBING -- UNTOUCHED SINCE THE FALL OF THE NAZIS. THIS LOOKS LIKE -- IN HERE, IT REALLY LOOKS LIKE WHAT YOU WOULD IMAGINE A BUNKER TO BE. I'M SORRY WE CAN'T GET IN HERE. UNFORTUNATELY, ONE OF THE WALLS INSIDE IT COLLAPSED. BUT SOON SASCHA AND THE BERLIN UNDERWORLDS' ASSOCIATION WOULD BE BACK TO INVESTIGATE AND PIECE TOGETHER THE CLUES OF THE PAST. I HAD JUST GOTTEN MY FIRST TASTE OF THE MYSTERY THAT IS BERLIN'S UNDERWORLD. THAT HAD CAVED IN, AND I'M PROBABLY GONNA LEAVE THIS BUNKER BUT I'M TOLD THERE ARE VAST LABYRINTHS OF BUNKERS IN THIS ENTIRE CITY. AND I'M GONNA FIND THEM. THOUSANDS OF BUNKERS ARE HIDDEN BENEATH THE STREETS OF BERLIN, BUT IT WAS NO EASY TASK TO PUT THEM THERE. "SWAMP," AND IT SITS IN THE LOWLAND PLAIN OF THE CREATED DURING THE ICE AGE. BUT BUILDING A CITY ON TOP OF THIS SWAMP MEANS YOU CAN'T DIG DOWN MORE THAN 10 FEET WITHOUT SO, HOW WAS HITLER ABLE TO BENEATH THE STREETS? HE CAN THANK ANOTHER INFAMOUS DICTATOR, NAPOLEON III, FOR PAVING THE WAY. AFTER THE PRUSSIANS DEFEATED FRANCO-PRUSSIAN WAR IN 1871, FRANCE WAS FORCED TO PAY REPARATIONS TO THE NEW GERMAN MOST OF THIS MONEY WENT BERLIN COULD FINALLY AFFORD TO UTILIZE THE EXPENSIVE BUT EFFECTIVE MODERN PUMPING TECHNOLOGY AND WATERPROOFING TECHNIQUES TO CREATE THEIR UNDERGROUND INFRASTRUCTURE. THE METRO WAS BUILT IN THE EARLY 1900s, AND THE FIRST 7 OF WATERTIGHT TUNNELS WERE CARVED 33 YEARS LATER, IN PREPARATION FOR THE IMPENDING WAR, GERMAN ENGINEERS LED BY HITLER'S BEGAN THEIR DIFFICULT AND SECRETIVE JOURNEY INTO THE UNDERGROUND. SINCE THEN, BERLIN'S UNDERWORLD HAS BEEN SYNONYMOUS WITH SECRECY. WHILE NAZI MONUMENTS AND BUILDINGS WERE TRANSFORMING THE SKYLINE, BENEATH THE GROUND, SUBTERRANEAN CONSTRUCTION WAS GOING ON AT A RATIO OF ONE TO THAT MEANS, FOR EVERY ONE FOOT OF CONSTRUCTION BERLINERS SAW ABOVE THE GROUND, THERE WAS AT LEAST THREE FEET OF CONSTRUCTION GOING ON BELOW. AND THIS HIDDEN WORLD OF HITLER'S IS STILL THERE. IT'S DANGEROUS, IT'S DARK, AND BURIED UP TO 150 FEET BENEATH THE GROUND. IT'S NOT EASY TO GET TO UNLESS YOU KNOW WHERE TO LOOK. >> WHEN HITLER CAME TO POWER, HE HAD PLANS TO TRANSFORM BERLIN INTO A CITY THAT WOULD RIVAL ANCIENT ROME. HE CALLED HIS VISION GERMANIA. AND LIKE THE ROMANS, HE COMMISSIONED STRUCTURES THAT WOULD BOTH AWE AND INTIMIDATE. MOST OF HIS PLANS WERE SHELVED WHEN THE WAR CAME IN 1939, BUT SOMEWHERE BENEATH THIS PARK, A PIECE OF GERMANIA STILL REMAINS. ARCHITECTURE HAD ALWAYS BEEN A PASSION OF HITLER'S, AND HE GERMANIA'S FUTURE MONUMENTS TIME WHEN NAZI GERMANY SEEMED LIKE A FARFETCHED FANTASY. BUT ON JANUARY 30, 1933, HITLER WAS NAMED CHANCELLOR OF GERMANY, AND HIS FANTASY WAS ABOUT TO BECOME REALITY. ONE OF HIS FIRST ORDERS OF BUSINESS WAS TO TRANSFORM BERLIN INTO A CITY WORTHY TO BE THE CAPITAL OF HIS HE WOULD CALL HIS NEW CITY GERMANIA AND WOULD MODEL HIS BUILDINGS AFTER THOSE OF ANCIENT ROME. TODAY REMNANTS OF HITLER'S DIETMAR. LET'S GET TO IT. >> SASCHA SENT ME TO MEET HIS COLLEAGUE, DIETMAR ARNOLD, THE CHAIRMAN OF THE BERLIN UNDERWORLDS' ASSOCIATION. >> HERE ON THIS PLACE, THERE WAS A FUHRER MONUMENT. >> DIETMAR IS AN URBAN HISTORIAN AND UNDERGROUND EXPERT. HE AND HIS GROUP HAVE MAPPED OUT HITLER'S HIDDEN MOST HAVE NO IDEA STILL EXISTS. >> SO, AGAIN, EXPLAIN TO ME. WHAT IS GERMANIA? >> GERMANIA WAS A NAZI URBAN PLANNING TO CHANGE BERLIN TO THE MAIN CAPITAL IN THE WORLD. NAZIS LIKE TO OCCUPY THE WHOLE BIG CAPITAL FOR THIS, YOU KNOW? BIG CAPITAL, HE NEEDED ONE THAT REICH. IT WAS, AS HE SAID, "THE WORD IN STONE." CONVEY THIS MESSAGE WAS ALBERT SPEER. SPEER AND HITLER SET OUT TO DIETMAR HAD THE PLANS TO PROVE IT. HE SHOWED ME BLUEPRINTS OF HITLER'S DREAM CAPITAL CITY, MOST OF WHICH WAS NEVER BUILT. BUT A SERIES OF UNDERGROUND TUNNELS WERE CONSTRUCTED, AND THEY STILL EXISTED BENEATH OUR AXIS TUNNELS, AND THEY WERE MEANT TO CARRY MILLIONS OF NAZI-DOMINATED WORLD. TIERGARTEN PARK. >> YOU LIKE A HELMET? >> YEAH, PLEASE. >> YOU NEED THIS. >> OKAY. >> OKAY. >> LET US GO. >> PULL ON THIS. >> ALL RIGHT. >> NOW YOU CAN COME. GOING INTO A TUNNEL FROM THE PAST. I CLIMBED DOWN OVER 50 FEET AND OVER 60 YEARS BACK IN TIME INTO WHAT THEY CALL "THE BLIND TUNNELS." >> OH, WOW. THIS IS IT, HUH? >> THIS IS ONE OF THE LAST PARTS OF GERMANIA. >> I'M NOT SURE HOW WELL I CAN SEE THIS, BUT I CAN SEE THE THE GROUND IS FLOODED OUT. IT LOOKS -- WHAT? -- ABOUT A CEILING MAYBE 20, 25 FEET HIGH. I SEE REBAR ALONG THERE, AND YOU HEAR A TREMENDOUS ECHO. >> HELLO! [ ECHOING ] IT'S LIKE IN THE MOUNTAINS. >> GERMANIA'S UNDERGROUND HIGHWAY TUNNELS WERE MEANT TO BE FINISHED IN 1950 AND WERE SUPPOSED TO BE ALMOST 8,000 FEET LONG. BUT ONLY 10% WERE COMPLETED, AND I WAS WALKING DOWN THE MIDDLE OF WHAT WOULD'VE BEEN HITLER'S FOUR-LANE HIGHWAY. THE HIGHWAY SAT 30 FEET BENEATH LEADING INTO HITLER'S DREAMWORLD. 750 FEET OF TUNNEL REMAINED THREE LEVELS DEEP. TWO LEVELS WOULD'VE CARRIED CARS IN AND OUT OF GERMANIA'S CAPITAL. AND THE DEEPEST LEVEL WAS FOR THE METRO. TODAY THE TUNNELS WERE FULL OF WATER SEEPING IN FROM THE WET CONCRETE. BUT IF HITLER HAD HIS WAY, I WOULD BE STANDING IN THE MIDDLE OF ONE OF THE MOST IMPORTANT HIGHWAYS IN THE WORLD, ONE THAT NERVE CENTER OF NAZI GERMANY. WE'RE LOOKING -- IT WOULD'VE BEEN HITLER'S HIGHWAY. THIS WOULD'VE BEEN THE HIGHWAY TO HIS DREAMWORLD, HIS GERMANIA THAT WOULD'VE LASTED 1,000 YEARS. AND THIS IS THE LAST LINK TO THAT. EVEN MORE IMPRESSIVE IS THEIR THESE CONCRETE WALLS WOULD'VE HAD TO SUPPORT THE MASSIVE WEIGHT OF THE BUILDINGS HITLER WAS PLANNING TO BUILD UP ABOVE. MEANT TO DWARF THE WORLD'S MOST FAMOUS STRUCTURES, LIKE ONE OF ARC DE TRIOMPHE IN PARIS. BUILD HIS OWN, ONLY HIS HAD TO BE FOUR TIMES HIGHER AND SIX TIMES WIDER THAN THE ONE IN PARIS. IT WOULD WEIGH OVER 400 TONS. THAT'S A LOT OF WEIGHT SITTING SANDY SOIL AND ON TOP OF HITLER'S SUBTERRANEAN HIGHWAY. BEGINNING. TWO HUGE, INTERSECTING BOULEVARDS. THE EXISTING "UNDER THE LINDEN STREET," WAS TO BE EXTENDED, AND THE ROAD WAS TO BE WIDENED TO 200 FEET. IT WOULD BE RENAMED THE EAST-WEST AXIS, AND CROSSING IT WOULD BE AN EVEN BIGGER ONE -- THE NORTH-SOUTH AXIS. THE NORTH-SOUTH AXIS WAS INSPIRED BY THE FAMOUS PARISIAN BOULEVARD, THE CHAMPS-éLYSéES. ONLY GERMANIA STREET WOULD BE 70 FEET WIDER AT A TOTAL WIDTH OF 400 FEET. THE 400-FOOT-TALL TRIUMPHAL ARCH WOULD SIT AT ITS HEAD. THIS NORTH-SOUTH AXIS WAS MEANT TO BE THE OFFICIAL PARADE ROUTE OF GERMANIA, AND THE TUNNELS DIETMAR AND I WERE EXPLORING BELOW ALLOWED IT TO STAY TRAFFIC-FREE. DWARFED BY THE OVERSIZED REICH, JUBILANT MASSES WOULD'VE BEEN USHERED ALONG THIS ROUTE LEADING TO THE VOLKSHALLE, OR "PEOPLE'S HALL." IT'S PRECISE LOCATION AT THE END OF THE PARADE ROUTE WOULD HAVE ACTUALLY REQUIRED DIVERTING THE RIVER SPREE. THE VOLKSHALLE WAS DESIGNED TO TOPPED WITH THE LARGEST DOME IN THE WORLD. THAT'S SIX TIMES LARGER THAN ITS INSPIRATION, THE PANTHEON 150,000 TO 180,000 PEOPLE COULD'VE FIT INSIDE. MADE ENTIRELY OF GRANITE, THE FOCAL POINT OF GERMANIA AND 550 TONS. BUT THE GREAT HALL WAS NEVER BUILT. IN FACT, MODERN ENGINEERS SAY THE BODY HEAT OF 170,000 PEOPLE IN THE DOME-SHAPED BUILDING WOULD'VE CAUSED SO MUCH PRECIPITATION, RAIN WOULD ACTUALLY FALL FROM THE CEILING. ROUTE WAS NEVER COMPLETED HITLER'S TRIUMPHAL ARCH. SPEER ESTIMATED HE COULD TRANSFORM THE ENTIRE FACE OF BERLIN BY 1950. PLANNING BEGAN IN 1935. ATTENTION WAS TURNED TO THE TUNNELS BENEATH THE PARK ARE ONE OF THE FEW THINGS LEFT OF HITLER'S ILL-FATED DREAMWORLD. TODAY OVER 50 FEET SEPARATED THEM WITH THE CITY HITLER ALONE PUTS FORTH OVER 6,000 POUNDS PER SQUARE FOOT OF PRESSURE. HOLD THE WEIGHT OF GERMANIA? EVEN SPEER WASN'T SURE. HE NEW HITLER'S GRAND PLANS WOULD TEST THE BOUNDS OF ENGINEERING. WITH HIS OWN TEST. HE BUILT THE GBK, OR SITE WITH SIMILAR SOIL ARCH. HE THEN POURED 12,650 TONS OF CONCRETE TO CREATE A STRUCTURE THAT MIMICKED THE GROUND PRESSURE OF ONE OF THE TWO FOOTINGS OF THE ARCH. THE GROUND PRESSURE OF THE GBK EQUALED 1.2 MEGA-NEWTONS PER SQUARE METER, OR OVER 10 TONS PER SQUARE FOOT. IF THE GROUND SANK MORE THAN 2 1/2 INCHES, BERLIN'S SOIL WOULD NOT SUPPORT THE ARCH AND MOST OF GERMANIA'S IMMENSE BUILDINGS. IT SANK 7 INCHES IN 3 YEARS, PROVING MANY OF HITLER'S BUILDINGS WOULD'VE BEEN IMPOSSIBLE TO BUILD. BUT HITLER DIDN'T ACCEPT THE SPEER WAS STILL LOOKING INTO WAYS TO FORTIFY GERMANIA'S SOIL WHEN BOMBS BEGAN TO FALL ON BERLIN IN THE SUMMER OF 1940. SHOULD THE WORLD STILL CARE ABOUT THIS PLACE? >> I THINK THAT IT'S NECESSARY TO SAVE THIS BECAUSE IT'S ONE OF THE LAST TRACES OF HIS GERMANIA AND IF YOU FILL THIS OR YOU DAMAGE THIS, YOU HAVE NOTHING CRAZY PLANNING OF HITLER. IF YOU NOT CAN REMEMBER TO YOUR HISTORY, THE DANGER IS REALLY HIGH THAT YOU CAN REPEAT IT. >> TO NEVER FORGET. >> YES. >> BERLIN IS OFTEN CALLED THE MOST REBUILT CITY IN THE WORLD. AFTER WORLD WAR II, ROUGHLY 60% OF ITS BUILDINGS WERE DESTROYED. EVEN TODAY, OLD BUILDINGS ARE NEW ONES. BUT THERE IS ONE PART OF REMAINS -- ITS UNDERWORLD. AFTER SEEING HITLER'S AND SPEER'S GRAND PLANS FOR GERMANIA, IT WAS OBVIOUS THEY WOULD NEVER DREAM OF BUILDING SOMETHING JUST TO HAVE IT IRONICALLY, TODAY THAT'S ALL THAT'S LEFT OF THEIR LEGACY. WHEN WAR BECAME IMMINENT, SPEER HAD NO CHOICE BUT TO DIRECT HIS ATTENTIONS UNDERGROUND. HIS TASK -- TO MAKE BERLIN BOMBPROOF. IT'S ESTIMATED THERE ARE OVER A THOUSAND BUNKERS BURIED BENEATH BERLIN. SOME WERE DESTROYED LIKE THE FUHRER BUNKER. LIKE THE ONE I HAD SEEN AT THE TRAFFIC MINISTRY. SOME ARE HIDDEN UNDER HOMES OR OFFICES, AND THERE'S EVEN ONE BENEATH THIS MAJOR METRO STOP. DIETMAR. >> HI. >> NICE TO SEE YOU. >> I MET UP AGAIN WITH UNDERGROUND EXPERT DIETMAR ARNOLD IN EAST BERLIN'S ALEXANDERPLATZ, OR "ALEXANDER PLACE." HE WASTED NO TIME SHOWING ME ONE OF THE BERLIN UNDERWORLDS' ASSOCIATION'S GREATEST FINDS. ALEXANDERPLATZ METRO, COMMUTERS WALK BY THIS INCONSPICUOUS DOOR EACH DAY. DIETMAR HAS ASKED US TO DISGUISE ITS LOCATION SO TO EXPLORE THIS DANGEROUS PIECE OF BERLIN'S UNDERWORLD ON THEIR WE HAD JUST ENTERED ONE OF BERLIN'S LARGEST UNDERGROUND CIVILIAN AIR-RAID SHELTERS. AND PEOPLE WAITING FOR THE METRO UP ABOVE HAVE NO IDEA WE WERE DOWN HERE. >> YOU LISTEN NOW TO THIS NOISE? THIS IS A SOUND FROM THE METRO. >> YEAH, YOU CAN HEAR THIS NOW, RIGHT? YOU CAN HEAR THE METRO. DURING WARTIME, THE RUMBLING ABOVE DIDN'T MEAN THE TRAIN HAD ARRIVED AT THE STATION... BUT THAT HUNDREDS OF BOMBERS HAD DESCENDED ON THE CITY. 2 MILLION TONS OF BOMBS AND EXPLOSIVE DEVICES WERE DROPPED ON BERLIN BY THE ALLIES DURING THE WAR. THAT'S NEARLY 800 TONS A DAY BY 1945. IN THE END, THE ESTIMATED DEATH TOLL FROM ALLIED BOMBINGS WAS ANYWHERE FROM 600,000 TO A MILLION PEOPLE. BY 1945, THERE WERE ONLY ENOUGH BUNKERS IN BERLIN FOR 10% OF THE POPULATION. BUT FOR THOSE WHO MADE IT INTO THIS GOVERNMENT-BUILT BUNKER, THERE ARE NO CONFIRMED RECORDS OF ANY BOMB-RELATED DEATHS. THAT'S PARTLY BECAUSE OF WHEN A BOMB FELL, THE SOFT SOIL WOULD HELP TO ABSORB THE SHOCK OF THE BLAST. THE BUNKER BELOW WOULD SWAY PEOPLE WOULD STAY INTACT. CONSTRUCTION OF THIS BUNKER. >> WELL, WE ARE HERE AROUND 12, 13 METERS AT ALEXANDER PLACE. AND WE HAVE HERE 3 UNDERGROUND LEVELS. 3 METERS, STILL CONCRETE. THE WALLS AROUND 2 METERS. THIS WAS ONE OF THE SAFEST BUNKER AROUND ALEXANDER PLACE. >> WALLS 6 FEET THICK. CONCRETE CEILINGS 10 FEET THICK. SANDY SOIL TO ABSORB THE SHOCK OF BOMBS. THAT'S OUTRAGEOUS COMPARED TO NORMAL BUILDING STANDARDS. IN FACT, THIS CEILING'S LIVE LOAD, OR THE TOTAL AMOUNT OF PRESSURE THE CEILING CAN HANDLE, IS 2,500 TIMES THE LOAD OF A NORMAL BUILDING. NORMAL BUILDINGS TODAY ARE CONSTRUCTED TO WITHSTAND A LIVE LOAD OF ONLY 75 TO 100 POUNDS PER SQUARE FOOT. THAT MEANS THE CEILING OF ALEXANDERPLATZ CAN SUPPORT MORE THREE 18-WHEELER TRUCKS PER DURING THE WORST BOMBING, 9,000 PEOPLE WERE CRAMMED DOWN HERE. >> THERE WAS A LOT OF PEOPLE IN THEY COULD NOT GO IN, AND THEN FOR ANOTHER PLACE, YOU KNOW? AND THERE WAS SOME SITUATIONS, FOR EXAMPLE, WHEN THEY OPENED THE BUNKER AFTER BOMB ATTACK, 50 PEOPLE LINED IN THE ENTRANCE GO IN. NOTICE IS THAT IT'S COLD DOWN HERE. WHEN CITIZENS, CIVILIANS, SOLDIERS CAME DOWN HERE, WERE THEY FREEZING DURING THE WINTER? >> YOU NEED NOT A HEATING SYSTEM 'CAUSE, IF ARE HERE 9,000 PEOPLE FAST, YOU CANNOT BELIEVE THIS. IT'S LIKE IF YOU GO INSIDE OF A SAUNA. >> THE AVERAGE PERSON HAS THE BODY HEAT EQUIVALENT TO THAT OF A 100-WATT LIGHT BULB. AND THERE'S 9,000 OF THESE IN HERE, SUDDENLY IT'S A SAUNA. >> IT'S LIKE A HEATING SYSTEM. >> SINCE THEY FIRST GAINED ACCESS IN THE LATE 1990s, DIETMAR AND BERLIN'S UNDERWORLDS' ASSOCIATION CONTINUE TO EXPLORE MORE CLUES TO UNLOCK THE SECRETS OF BERLIN'S DARK PAST. AND ON A VISIT LAST YEAR, THEY FOUND ONE. THEY WERE DRILLING A HOLE TO WALL. POPPED OUT INTO A HOLLOW SPACE. THEY PUT A TINY CAMERA THROUGH THE HOLE AND SAW A LARGE TUNNEL. >> A A TUNNEL GOING THIS DIRECTION AND A TUNNEL GOING THIS DIRECTION, AND NOBODY KNOW WHAT'S BEHIND, REALLY. >> THERE'S ANOTHER BUNKER BEHIND >> IT'S POSSIBLE. >> SO IT MAY BE A TIME CAPSULE THAT'S NEVER BEEN OPENED. >> MAYBE. >> MY NEXT STOP WAS A EAST BERLIN. I MET UP WITH DIETMAR'S UNDERWORLD PARTNER, SASCHA KEIL. >> ERIC. >> NICE TO SEE YOU AGAIN. AROUND SOME MORE. I APPRECIATE IT. >> WE WERE IN THE NEIGHBORHOOD OF KREUZBERG, WHICH WAS ALMOST COMPLETELY DESTROYED DURING WORLD WAR II. BUT ONE ODDLY SHAPED BUILDING REMAINED FROM THAT TIME. THE BUILDING WAS CALLED THE GASOMETER AND STOOD 69 FEET HIGH AND 184 FEET WIDE. IT WAS ORIGINALLY BUILT IN 1846 AS A SUBSTATION OF BUT THE INTRODUCTION OF ELECTRIC STREET LAMPS IN THE LATE 1800s MADE THIS SUBSTATION IN 1940, THE GERMANS CONVERTED IT INTO A BUNKER, BUT THIS WAS NO ORDINARY BUNKER. FEW OTHERS BEFORE HAD PERFECTED ABOVE-THE-GROUND BUNKERS LIKE THE NAZIS, BUT THEY HAD TO SINCE THEY WERE RUNNING OUT OF NEEDED TO CONTINUE BUILDING THEY STARTED LOOKING FOR EXISTING BUILDINGS TO FORTIFY. THE GASOMETER, OR FICHTEBUNKER, FIVE STORIES WERE ABOVE THE BUT ALL SIX FLOORS WERE FORTIFIED AND INCREDIBLY SAFE. >> LET'S GO IN. THIS IS THE ONLY REMAINING ENTRANCE TO THE BUNKER. ERIC, PLEASE COME IN. >> YOU CAN SMELL -- IT SMELLS LIKE MOTOR OIL, LIKE A GARAGE. >> YES, YES, YES. IT'S FROM THE DIESEL. >> I'M SMELLING DIESEL, OKAY. THE STRONG SMELL OF DIESEL WAS COMING FROM THE BASEMENT, WHERE SASCHA TELLS ME THERE'S A DIESEL-POWERED GENERATOR LEFT OVER FROM THE 1940s. IT'S A GENERATOR LARGE ENOUGH TO POWER THIS FORTIFIED CITY THAT HAD A POPULATION OF 6,500. I WAS BARELY INSIDE, BUT I COULD TELL THIS PLACE WAS MASSIVE AND DISORIENTING. I COULDN'T TELL IF I WAS ABOVEGROUND OR BELOW. ONCE A CAVERNOUS HOLE FOR SIX SEPARATE FLOORS CONNECTED BY FIVE STAIRWELLS AND THREE LIFTS. EACH FLOOR HAD 120 ROOMS. 25 KITCHENS, A HOSPITAL ON EACH BOTTOM LEVEL. TRULY A CITY OF ITS OWN. SO, THIS IS A ROW OF TOILETS. AND HERE YOU GO. I'M IMAGINING THEY WERE IN A BETTER STATE 60 YEARS AGO. "BESETZT"? >> YES. >> WHAT IS "BESETZT"? >> IT'S LOCKED. >> SO THIS SAYS "LOCKED." YOU CAN SEE SOMEONE'S INSIDE. >> THE WAR'S OVER. YOU CAN COME OUT NOW. THE FICHTEBUNKER EVEN HAD ITS OWN POST OFFICE, USED TO COMMUNICATE WITH OTHER BUNKER CITIES IN BERLIN. >> REIS POST. IT'S A POST SYSTEM IN GERMANY. >> TELEGRAPHS, TELEGRAMS, PHONE -- THIS IS WHERE IT WOULD COMMUNICATION FROM BUNKER TO BUNKER WASN'T UNCOMMON. THESE FORTIFIED CITIES MADE EVERY ATTEMPT TO MAINTAIN SOME SEMBLANCE OF ORDER IN SPITE OF THE CHAOS OUTSIDE. YOU SEE THE CHAMBER NUMBERS. >> SO THAT'S RAUM, OR ROOM, 172 TO 138 THAT ARE OVER THERE. THIS IS ROOM 198 TO 231. THIS TELLS YOU WHERE THE IT'S LIKE A DORMITORY. DORMITORY. FICHTEBUNKER HAD MANY SIGNS AND ORIENTATION DEVICES... >> EINGANG IS "ENTRANCE." >> ENTRANCE. ...BUT AN EXTREMELY CONFUSING LAYOUT. >> ANOTHER IN A RING OF ROOMS RIGHT HERE, JUST LIKE THE OUTER RING. IT'S JUST A LABYRINTH, A CIRCLE OF ROOMS THAT KEEP GOING AROUND. SASCHA TOLD ME IT WAS DONE ON PURPOSE, NOT TO CONFUSE PEOPLE, BUT BOMBS. THE SAFEST PLACE TO BE IN THE BUNKER WAS THE CENTER. FICHTEBUNKER WAS BUILT WITH THREE CIRCULAR RINGS, AND INSIDE EACH RING WERE ROOMS WHOSE ANGLED WALLS HELPED TO IT'S SIMPLE PHYSICS. BY THE TIME THE ENERGY OF THE BLAST GETS TO THE CENTER OF THE BUNKER, IT HAS BEEN LESSENED 30% BY EACH 90-DEGREE ANGLE IT HOW DID THEY CHANGE THE INTERIOR OF THIS BUILDING FROM A GAS-STORAGE FACILITY TO A BUNKER WITH 1,200 ROOMS, WITH KITCHENS, WITH BATHROOMS. HOW DID THEY DO THAT? >> THEY FILLED IN THE CONCRETE. IT WAS NOT SO DIFFICULT BECAUSE AN EXISTING WALL OF BRICKS WAS HERE AND METAL RINGS IN IT, AND SO THEY ONLY HAD TO FILL THE >> SO THIS WAS ALREADY A SOMEWHAT-FORTIFIED BUILDING BECAUSE OF ITS NATURE. HOW MUCH MORE CONCRETE DID THEY ADD TO THE BRICK STRUCTURE THAT WAS ALREADY HERE? >> ABOUT 2 METERS. >> 6 MORE FEET OF CONCRETE WAS ADDED TO THE ALREADY 5 FEET OF EXISTING BRICK. THAT MADE THE WALLS NEARLY 12 FEET THICK. ON TOP OF THAT, THE WALLS OF THE 720 INNER ROOMS WERE ALL MADE OF REINFORCED CONCRETE, THE KEY INGREDIENT TO NAZI BUNKER-BUILDING TECHNIQUES. THIS BUNKER SAVED UPWARDS OF 30,000 PEOPLE FROM ALLIED BOMB ATTACKS. AFTER THE WAR, IT BECAME A SHELTER FOR GERMANS WHO HAD LOST THEIR HOMES. LATER IT WAS FILLED WITH ENOUGH FOR TWO FULL DAYS DURING THE EAST GERMAN BLOCKADES OF THE WEST. THIS LOOKS LIKE CARROTS. >> YEAH, THERE IS 7,000 TONS OF BUILDING. >> AH, SALTED CARROTS -- DELICIOUS WHEN YOUR CITY GETS BLOCKADED. TODAY THIS GASOMETER TURNED BUNKER TURNED SHELTER TURNED FOOD STORAGE MAY BE TURNED INTO CONDOMINIUMS. JUST ANOTHER EXAMPLE OF THE CHANGING FACE OF BERLIN. >> NEXT STOP, HUMBOLDTHAIN PARK IN EAST BERLIN. IT'S HILLY LANDSCAPE IS A FAVORITE FOR JOGGERS AND TOURISTS, WHO CLIMB TO THE TOP VIEWS. ALWAYS AS THEY SEEM. AND THE NAZI FORTRESS PEEKING OUT FROM BENEATH THE SOIL THE FORTRESS IS CALLED THE FLAK TOWER, AND IT WAS ONE OF THREE BUILT IN BERLIN BY THE IT WAS AND STILL IS CONSIDERED A FEAT OF GERMAN ENGINEERING. AT OVER 140 FEET HIGH AND FLAK TOWER OF HUMBOLDT WAS THE PERFECT VANTAGE POINT FOR THE NAZIS TO OBSERVE MOVEMENT OF SOVIET TROOPS AND TO FIRE AT ALLIED PLANES FROM BUILT FROM REINFORCED CONCRETE, THE FLAK TOWER HAS 12-FOOT-THICK FOUNDATIONS, 8 1/2-FOOT-THICK OUTSIDE WALLS, AND 5-FOOT-THICK INTERIOR WALLS. THE ROOF WAS 12 1/2 FEET THICK. BUILDING. AT THE END OF THE WAR, SOVIET FLAK TOWER AND WERE FIRING STRAIGHT, BUT NOTHING COULD BRING IT DOWN. THREE YEARS AFTER THE WAR ENDED, THE FLAK TOWER AND EVERYTHING REMINISCENT OF HITLER'S MILITARY MIGHT WAS ORDERED TO BE DESTROYED. ALLIED FRENCH TROOPS TRIED OF TNT AND ONLY SUCCEEDED IN CRUMBLING THE SOUTHEAST SIDE. THE NORTH SIDE STILL REMAINS INTACT, ALBEIT BURIED BENEATH THE RUBBLE OF OLD BERLIN. MANY HILLS OR MOUNTAINS IN BERLIN. >> THERE WERE NOT MANY. AFTER THE WAR, WE HAD SOME MORE. >> MORE<i> AFTER</i> THE WAR. YOU'LL HAVE TO EXPLAIN THAT. THAT'S A LOADED ANSWER THERE. >> THEY ARE ARTIFICIAL LIKE THIS ONE. >> THIS IS AN ARTIFICIAL MOUNTAIN? >> YES. >> YES. >> BERLIN'S LANDSCAPE IS TOPOGRAPHICAL MAP, AND IT APPEARS OTHERWISE. THAT'S BECAUSE THE HILLS YOU SEE AREN'T NATURAL FORMATIONS. THE RUBBLE HILLS WERE ERECTED IN THE LATE 1940s AND EARLY 1950s DURING A MASSIVE CLEANUP BY THE ALLIES OF WAR-TORN BERLIN. SASCHA TOLD ME THAT, AFTER THE WAR, 80% OF THE STREETS IN CENTRAL BERLIN WERE DESTROYED. THAT MEANT THE PAVEMENT, THE PATH OF ALLIED BOMBS WOULD'VE BEEN IN RUINS AND BURIED BENEATH MY FEET. BUT I WANTED TO SEE FOR MYSELF. I WAS ABOUT TO DIG INTO A HILL MADE OF 60 MILLION CUBIC FEET DIRECTLY ON TOP OF THE SO, IF WE DIG RIGHT HERE, I'M GONNA FIND THE RUINS OF BERLIN. >> YES. >> ALL RIGHT, LET'S DO IT. DEFINITELY HIT SOMETHING KIND OF HARD HERE, RIGHT? THAT DIDN'T TAKE TOO LONG, DID IT? HERE'S CONCRETE. THIS WE DON'T EVEN HAVE TO DIG. IT'S RIGHT HERE AT THE SURFACE. LOOK. HERE YOU GO. THIS IS ALL FROM BERLIN. OF HISTORY LYING JUST INCHES BENEATH OUR FEET. IT'S A BIG MOUNTAIN. HERE'S MORE. NEWLY CONSTRUCTED 1940s HOMES WERE MIXED UP WITH PRUSSIAN PALACES AND CARTED BY THE TRUCKLOAD TO THIS VERY SPOT. SINCE THEY COULDN'T DESTROY IT, THE PLAN OF THE ALLIES WAS TO IMPRESSIVE FLAK TOWER BENEATH THE RUBBLE OF WAR-TORN BERLIN. THE EAST, WEST, AND SOUTH SIDE WENT OFF WITHOUT A HITCH. GRASS AND TREES WERE PLANTED, AND THE NEW HILL TOOK ROOT. BUT THE NORTH SIDE OF THE THE U-BAHN RAIL. PILING RUBBLE THAT WOULD WOULD BE FAR TOO DANGEROUS, SO THE NORTH FACE WAS LEFT OPEN. AND LUCKY FOR US, THAT'S HOW WE WERE GOING TO GET IN. SASCHA AND I MET UP WITH REINERT JANICK... >> THIS IS OUR EXPERT FOR TODAY. >> ...A FLAK TOWER AUTHOR AND REINERT,<i> GUTEN TAG.</i> THANK YOU VERY MUCH FOR MEETING WITH US. SASCHA OFFERED TO TRANSLATE AS REINERT LED ME THROUGH THE 7-LAYERED FORTRESS. THIS CONCRETE STRUCTURE TOOK ONLY SIX MONTHS TO BUILD AND WAS BRACED WITH STEEL RODS, A TECHNIQUE PERFECTED BY THE GERMANS THAT RENDERED THEIR MY GOSH. YOU KNOW WHAT? IF I DIDN'T SEE HOW REINFORCED WHOLE BUILDING, IT WOULD LOOK AS IF THIS IS MADE OF CARDBOARD, >> THIS IS ORIGINAL STAIRWELL. >> THIS IS THE ORIGINAL STAIRWELL. TOWER TWO. >> FOURTH LEVEL. >> WE WERE ON THE FOURTH LEVEL OF A SEVEN-STORY BUILDING, AND 60 FEET BENEATH THE GROUND. STRICTLY FOR MILITARY USE, WITH OBSERVATION POSTS AND AN ANTI-AIRCRAFT GUN PLATFORM. BELOW WAS A BUNKER FOR 35,000 CIVILIANS AND 2,000 THE FLAK TOWER WAS SO SECURE, HITLER ORDERED PRECIOUS ARTIFACTS AND ARTWORKS ONCE HOUSED IN BERLIN'S MUSEUMS TO BE STORED HERE. MOVIE THEATER. >> IT'S LIKE A SMALL TOWN. >> IT'S A SMALL TOWN. THIS IS A FORTIFIED VILLAGE. FRENCH ATTEMPTS TO DESTROY THE ALL OVER THE FLOORS. SO, THIS IS THE HANDIWORK OF THE FRENCH, RIGHT? NOW WE'RE DESCENDING TO ANOTHER >> BE CAREFUL. >> THIS IS A WEAPON? >> THIS LOOKS LIKE A PIPE, BUT WITH AN EXPLOSIVE HEAD IN FRONT, AND THEN IT WAS FIRED. AND WHAT WAS LEFT WAS THE PIPE. >> IT'S ONLY FOR ONE USAGE. >> RIGHT, THIS WAS ONLY ONE USE. QUITE AN EERIE REMNANT... FROM THIS TIME. THIS IS WHERE YOU GET A SENSE OF THE WIDTH. HOW WIDE FROM WALL TO WALL? >> IT'S 70 METERS. >> 70 METERS WIDE. >> 72 METERS. >> 72 METERS, OKAY. 72 METERS, OR 236 FEET, WOULD NORMALLY BE AN EASY TARGET, BUT SOUTHEAST SIDE REVEALED A SPIDER WEB OF STEEL REBAR INSIDE THE THICK CONCRETE. LOOK AT THE REINFORCED STEEL. AND TO ME, IT LOOKS REDUNDANT. HOW MUCH REBAR IS IN THIS BUILDING? >> WE HAVE, IN ONE CUBIC METER OF CONCRETE, ABOUT 50 KILOS OF STEEL. FEET OF CEMENT. NORMAL CONCRETE CONSTRUCTION TODAY USES APPROXIMATELY 3,300 POUNDS OF STEEL. SO CONTEMPORARY BUILDINGS WILL HAVE MAYBE A THIRD TO A QUARTER OF THAT IN A TYPICAL BUILDING, >> YOU'RE RIGHT. >> TODAY THE FLAK TOWER SITS ABANDONED, 140 FEET BENEATH THE RUBBLE OF HUMBOLDTHAIN PARK. AND WHILE SASCHA AND HIS GROUP CONTINUE TO TRY TO PIECE TOGETHER ITS PAST, EXACTLY WHAT WENT ON INSIDE ITS WALLS REMAINS A MYSTERY. >> THIS WAS A SECRET BUILDING. IT WAS A MILITARY BUILDING, AND SO IT WAS A GUARDED SECRET. AND WE HAVE NO ORIGINAL PICTURES FROM THE INSIDE. >> SO WE HAVE TO SPECULATE. >> YES. >> SPECULATION IS COMMON IN A CITY LIKE BERLIN... A CITY WHOSE SECRETS ARE ONLY NOW COMING TO THE SURFACE. >> LONG BEFORE THE BERLIN WALL DIVIDED THE CITY, HITLER'S DELUSIONS NEARLY DESTROYED IT. BERLIN WAS A COSMOPOLITAN CAPITAL. IT WAS KNOWN FOR ITS LIBERAL TODAY THE BEER GARDEN IS THERE'S NO SHORTAGE OF THEM BUT HERE BEER IS MUCH MORE THAN JUST A COLD DRINK. THIS CONCOCTION OF WATER, IS A DEEP-SEATED TRADITION IN GERMANY'S HISTORY, A TRADITION THAT RELIED ON THE DEPTHS OF HELLO, INGMAR. >> HOW ARE YOU? >> NICE TO MEET YOU. THANK YOU. I WAS EXPECTING YOU TO GREET ME WITH BEER. >> OH, MAYBE WE HAVE ANOTHER BEER AFTERWARDS. >> INGMAR ARNOLD, AN UNDERGROUND SPECIALIST AND BEER CONNOISSEUR, WAS SHOWING ME THE REMAINS OF THE BETZEL FAMILY BREWERY LOCATED IN TODAY'S EAST BERLIN. FROM 1846 TO 1948, THE BETZEL FAMILY WAS THE LARGEST PRIVATE BREWERY IN BERLIN. A 120,000 LITERS OF BEER AND HAD A SUBTERRANEAN STORAGE THAT'S OVER 110,000 BOTTLES OF GERMANS ARE RENOWNED FOR THEIR BEER MAKING. WHAT DO THEY DO BETTER? >> THIS IS A PURITY RULE. JUST THE MAIN, BASIC ELEMENT OF BEER -- HOP AND GRAIN AND WATER. NOTHING ELSE. YOU MAKE THE BEST BEER IN THE WORLD. THIS IS THE SECRET. >> THE BREWERS OF BERLIN WANTED TO SEPARATE THEIR BEER-BREWING TECHNIQUES FROM THE ONES OF THEIR BAVARIAN NEIGHBORS TO THE INSTEAD OF THE AGE-OLD ALE, THEY WOULD BREW LAGER, AND THEY NEEDED THE COLD, DAMP SPACES OF BERLIN BREWERS NEEDED TO KEEP THEIR NEW, REVOLUTIONARY LAGER FAHRENHEIT FOR AT LEAST 30 DAYS BEFORE IT WAS READY TO DRINK. ELECTRICITY FOR REFRIGERATION, SO NECESSITY BECAME THE MOTHER THEY NEED IT UNDERGROUND. AND THEY FOUND IT HERE. AND THEY COULD GO INTO THE THE BEER HERE. THEREFORE, THE BREWERS INVENTED THE BERLIN UNDERGROUND. >> BEFORE THERE WERE BUNKERS, NAME MEANS "SWAMP." HOW, LONG BEFORE HITLER BUILT ABLE TO MASTER THE COMPLEX DIGGING AND PUMPING TECHNIQUES NECESSARY TO GO UNDERGROUND? THEY DIDN'T. INSTEAD, THEY FOUND ONE OF THE FEW HILLS IN BERLIN, MOVED THEIR FACTORY ON TOP OF IT, AND 80 FEET INTO ITS DRY, ROCKY SOIL. THERE WERE 15 TO 20 ROOMS, EACH 20 FEET TALL AND 20 FEET WIDE, TRACKS FOR SMALL CARTS TO CARRY THE BARRELS, AND EVEN ROOMS FOR THE BEERMEISTER TO TEST HIS BREW. BEFORE HITLER OR THE METRO EVER BROKE GROUND, THEY HAD SUCCEEDED IN CREATING BERLIN'S FIRST UNDERGROUND CITY. >> WELCOME TO THE UNDERWORLD OF BERLIN. RIGHT HERE, OR STORAGE AREA RIGHT HERE. >> THEY ARE VERY, VERY MORE THAN 20,000 SQUARE METERS ARE JUST LYING 20 METERS BENEATH THE STREETS OF BERLIN. >> THAT'S APPROXIMATELY 65 FEET BENEATH THE BUSTLING FORMER FACTORY ABOVE AND TONS OF PRESSURE ON THE CELLARS BELOW. BUT THESE CELLARS WERE BUILT TO LAST. ARCHED CEILINGS HELP SUPPORT THE PRESSURE, AND THE ROCKY SOIL IT'S DUG INTO GIVES IT A THIS IS AN IMMENSE STRUCTURE. WE'VE GOT A CEILING THAT'S PROBABLY 25 FEET HIGH. I'M GUESSING ON THE WIDTH ABOUT 20 FEET. SEE THERE'S OTHER ROOMS, LOOK AT THE SIZE OF THESE. WITH BEER, RIGHT? TO THE WALLS, TO THE CEILING, FILLED WITH BEER. ONCE THE LAGER HAD COOLED FOR A MONTH, WOODEN BARRELS WERE UP ABOVE TO DELIVER FRESH AND COLD LAGER TO THE BEER GARDENS OF BERLIN. BEER DRINKING GOING ON IN THE GARDENS. >> POLITICAL PARTIES LIKE THE COMMUNISTS, SOCIAL DEMOCRATS, AND NAZIS USED THE LURE OF FREE BEER TO WIN VOTES. AND WHAT BETTER PLATFORM THAN AT A BEER GARDEN, WHERE 200 TO 300 CITIZENS GATHERED EACH DAY TO HAVE A DRINK? SPEECH IN MUNICH IN A BEER AND HIS ARCHITECT, ALBERT SPEER, WAS FIRST INTRODUCED TO HITLER AFTER A BEER-GARDEN PERFORMANCE IN 1930. BEER HALLS HAD GIVEN HITLER HIS RISE TO FAME. NOW THEY'D PROVIDE HIM WITH THE ON THE WORLD. THESE SAME ROOMS THAT ONCE STORED BETZEL'S FAMOUS BEER WERE TURNED INTO A WAR-MAKING FACTORY IN 1939. >> THEY MADE RADAR EQUIPMENT AND FOR THE MASS COMMUNICATIONS AMONG THE ARMY. BECAUSE THIS PRODUCTION WAS SO PRODUCTION SITE INTO THE UNDERGROUND, THAT IT WOULDN'T BE DESTROYED BY THE PLANES. >> AND HOW COME BETZEL WAS WIPED OUT AFTER THE WAR? >> BECAUSE, AFTER THE WAR, THIS PART BECAME A PART OF EAST BERLIN, AND THE COMMUNIST ENTERPRISES LIKE THE BETZEL >> IT ALSO DIDN'T HELP THAT BEER PRODUCTION DURING THE NAZI REGIME. LEGACY OF BETZEL BEER, JUST AS IT TARNISHED THE ONCE-BRIGHT FUTURE OF BERLIN. A MADMAN, A SOIL FULL OF SECRETS. IN LESS THAN 100 YEARS, BERLIN WENT FROM A SWAMPY PRUSSIAN PROVINCE TO THE BATTLEGROUND OF THE 20th CENTURY. AND ITS UNDERGROUND ALL TODAY A GROUP OF MODERN-DAY BERLINERS ARE ADDING THEIR OWN DARING TO DIG UP THE SECRETS OF THE PAST. AS EYEWITNESSES DIE AND NEW CONSTRUCTION COVERS UP CLUES, THEIR JOB GETS HARDER AND HARDER. >> WE SEE THE STREETS AND THE WHOLE CITY WITH OTHER EYES. OTHERS ARE LOOKING FOR THE CLOUDS, AND WE LOOK FOR THE GROUND. >> BUT THE SEARCH HAS ONLY JUST BEGUN. >> WE HAVE WORK FOR GENERATIONS. THERE ARE SO MANY SECRETS, OUR WORK, IT WILL BE NEVER DONE. >> IN LESS THAN 10 YEARS, THE BERLIN UNDERWORLDS' ASSOCIATION SURFACE. TELLING WHAT THEY WILL HAVE FOUND.
