>> YOU.

>> 80 YEARS AGO.

6th, 1945, THE UNITED STATES DROPPED AN ATOMIC BOMB ON HIROSHIMA BENEATH THE MUSHROOM CLOUD, THERE EMERGED THE MOST HORRIFIC SCENE IN HUMAN HISTORY.

GROUND ZERO.

THE AREA WITHIN A 500 METER RADIUS BECAME A ZONE OF DEATH, WHERE VIRTUALLY NO LIVING THING SURVIVED.

SO MANY LIVES WERE LOST THAT THE DETAILS OF WHAT REALLY HAPPENED.

THERE ARE STILL UNKNOWN AND YET, AT LEAST 78 PEOPLE SOMEHOW MANAGED TO SURVIVE THEY LEFT BEHIND 110 HOURS OF RECORDINGS IN WHICH THEY DESCRIBED THE EXPERIENCE.

ONLY 78 PEOPLE LIVED TO DESCRIBE THE SCENE AT GROUND ZERO.

WHAT WAS IT ACTUALLY LIKE WE USE THE LATEST SCIENTIFIC TECHNIQUES TO ANALYZE WHAT HAPPENED AT GROUND ZERO, BASED ON SURVIVOR INTERVIEWS.

THEIR ACCOUNTS WERE TRANSFORMED INTO VISUAL IMAGES FOR THE FIRST TIME HOW DID THE ATOMIC BOMB DESTROY HUMAN LIFE?

80 YEARS ON, NUCLEAR WEAPONS ARE A GROWING, WORLDWIDE THREAT.

WHAT FOLLOWS IS A WARNING FROM GROUND ZERO IN HIROSHIMA DOCUMENTS AND AUDIO RECORDINGS OF THE 78 SURVIVORS ARE KEPT IN THIS RESEARCH INSTITUTE AT HIROSHIMA UNIVERSITY.

AS THE NUMBER OF LIVING ATOMIC BOMB SURVIVORS CONTINUES TO DECLINE, WE WERE GIVEN PERMISSION TO ANALYZE THESE DOCUMENTS IN DETAIL.

FOR THE FIRST TIME.

THEY INCLUDE RECORDS DETAILING THEIR HEALTH CONDITIONS AND MEDICAL HISTORIES.

ALONG WITH FOLLOW UP STUDIES THAT CONTINUED THROUGHOUT THEIR LIFETIMES THE TAPES WERE MADE IN THE 1970s AND 1980s.

HIROSHIMA UNIVERSITY AND OTHER INSTITUTIONS CONDUCTED COUNTLESS INTERVIEWS, WHICH EVENTUALLY LED TO THE DISCOVERY OF THE 78 SURVIVORS.

TODAY, GROUND ZERO IS HOME TO THE HIROSHIMA PEACE MEMORIAL PARK.

THE AREA INCLUDED HIROSHIMA’S LIVELIEST SHOPPING DISTRICT.

THE U.S.

CHOSE THE CITY AS A TARGET, AS THERE WERE SEVERAL MILITARY FACILITIES IN THE AREA.

IT’S ESTIMATED THAT SOME 21000 PEOPLE WERE AT GROUND ZERO.

ON AUGUST 6th, 1945.

EACH OF THE 78 SURVIVORS WAS ENGAGED IN THEIR USUAL MORNING ROUTINES.

AT NATIONAL SCHOOLS.

THE SUMMER VACATION HAD BEEN SIGNIFICANTLY SHORTENED, AND THE CHILDREN WERE REQUIRED TO GO TO WORK.

THERE WERE ALSO APPROXIMATELY 3000 WOODEN TENEMENTS.

EVERYTHING SEEMED PERFECTLY NORMAL.

IT WAS RUSH HOUR, SO THE STREETCARS WERE ALMOST FULL.

AROUND TEN CARS WERE IN SERVICE.

THE MORNING BUSTLE WAS AT ITS PEAK.

THE ATOMIC BOMB DETONATED 600M ABOVE THE GROUND.

AT THAT MOMENT, A HUGE BALL OF FIRE APPEARED IN THE SKY.

POWERFUL RAYS OF HEAT WERE RELEASED OKUNIKKO TAKAICHI WAS ON A BUSINESS TRIP FROM A NEIGHBORING PREFECTURE HE AND A COLLEAGUE WERE WALKING TO THEIR OFFICE.

KANEKO WAS JUST 270M FROM THE HYPOCENTER.

WHAT HAPPENED THERE AT THAT MOMENT?

SOME ARTIFACTS PROVIDE CLUES.

STONE STEPS ON DISPLAY AT THE HIROSHIMA PEACE MEMORIAL MUSEUM.

SHOW THE SHADOW OF A PERSON WHO APPEARED TO HAVE BEEN KILLED INSTANTLY BY THE HEAT RAY OUR INVESTIGATION REVEALED THAT KANEKO WAS EXPOSED TO THE BLAST.

JUST 25M FROM WHERE THESE STEPS WERE LOCATED.

WHEN GRANITE IS EXPOSED TO STRONG HEAT RAYS.

THE HEATED SURFACE IS REMOVED AND TURNS WHITE.

THE SHADOW WAS THE OUTLINE OF A PERSON WHO HAD BLOCKED THE FEROCIOUS HEAT RAY, WHICH ALLOWED THE SURFACE OF THE STONE TO STAY INTACT PROXIMITY TO THE SHADOW STONE.

A SPLIT SECOND ACTION JUST BEFORE THE BLAST PREVENTED KANEKO FROM BEING HIT DIRECTLY BY THE HEAT RAY.

THE SHADOW OF A CONCRETE BUILDING SAVED HIM FROM CERTAIN DEATH.

HOWEVER, HE SUFFERED SEVERE BURNS ON THE LEFT SIDE OF HIS BODY, WHICH WAS TURNED TOWARD THE HYPOCENTER.

HIS EAR BECAME INFECTED AND HAD TO BE REMOVED.

THE TREMENDOUS HEAT RAY ALSO HIT YOUNG STUDENTS NATIONAL SCHOOL WAS LOCATED ABOUT 400M FROM THE HYPOCENTER.

AN ESTIMATED 400 STUDENTS WERE THERE THAT DAY.

WAS IN THE SIXTH GRADE SHE SHARED SOME MEMORIES OF THAT DAY.

IMARI WAS ABLE TO ESCAPE BECAUSE SHE WAS INSIDE A REINFORCED CONCRETE BUILDING, WHICH WAS RARE FOR SCHOOL BACK THEN.

SHE THEN FELT HER WAY THROUGH THE DARKNESS AND OUT INTO THE SCHOOLYARD.

OF THE ESTIMATED 400 STUDENTS WHO WERE THERE THAT DAY, IMARI WAS THE ONLY SURVIVOR BUT THE PEOPLE WHO WERE SHELTERED FROM THE HEAT RAYS IN BUILDINGS FACED ANOTHER THREAT THE SHOCK WAVE.

THIS POWERFUL BLAST OF AIR WAS PRODUCED BY THE TREMENDOUS PRESSURE GENERATED BY THE NUCLEAR EXPLOSION.

IT SPREAD ACROSS THE CITY AT SUPERSONIC SPEED.

THE FORESTS AROUND THE HYPOCENTER WAS AROUND 20 TONS PER SQUARE METER.

MANY OF THE 2000 PEOPLE AT GROUND ZERO WERE IN WOODEN TENEMENTS, WHICH WERE INSTANTLY CRUSHED BY THE BLAST THE DAMAGE WAS NOT LIMITED TO FRAGILE STRUCTURES.

THE SEVEN STORY REINFORCED CONCRETE FUKOKU BUILDING IN THE FINANCIAL DISTRICT WAS ALSO BADLY DAMAGED.

THE SHOCK WAVE BROKE THROUGH THE GLASS AND ENTERED THE BUILDING 15 YEAR OLD TOKUKO HIROKO WAS ON THE FOURTH FLOOR DURING THE BLAST.

HER MEDICAL RECORDS INDICATE THE FEROCITY OF THE SHOCK WAVES.

THIS IS AN X-RAY OF HER ARM.

A FIVE CENTIMETER LONG SHARD OF GLASS HAD DEEPLY EMBEDDED ITSELF DOWN TO HER WRIST.

BONE.

TOKYO SPOKE OF A STRANGE SENSATION SHE FELT AT THE MOMENT THE EXPLOSION OCCURRED.

OF THE 117 PEOPLE AT TOKYO’S WORKPLACE, MORE THAN 100 ARE PRESUMED TO HAVE BEEN KILLED INSIDE THE BUILDING EXACTLY HAPPENED WHEN THE SHOCKWAVE HIT THE STURDY BUILDING WE CREATED A MODEL OF HIROSHIMA CITY AT THE TIME TO HELP VISUALIZE THAT MOMENT AN ADVANCED HIGH SPEED CAMERA SHOWS THE SHOCK WAVE SPREADING OUT AT SUPERSONIC SPEED WHEN IT HITS A BUILDING OR THE GROUND.

COUNTLESS FINE WAVES ARE GENERATED IN THE FINANCIAL DISTRICT, SHOCK WAVES WERE REFLECTED IN ALL DIRECTIONS AND ENGULFED THE BUILDING WHERE TOKUKO WAS WORKING.

A COMPLEX WEB OF REFLECTED WAVES WAS GENERATED INSIDE THE BUILDING A SIMULATION WAS CONDUCTED OF THE SHOCKWAVE HITTING THE FIRST FLOOR OF THE FUKOKU BUILDING.

THE HIGH PRESSURE AREAS ARE INDICATED IN RED.

THE WAVES BOUNCED OFF THE WALLS AND CEILING AND INTERMINGLED.

THE AIR PRESSURE INSIDE THE BUILDING DOUBLED THE RIPPLING SENSATION TOKYO FELT IN HER HEAD MAY BE EVIDENCE THAT SHE WAS EXPERIENCING THE SHOCK WAVES REVERBERATING INSIDE THE BUILDING.

SHE THEN FLED THE BUILDING AND SAW A SHOCKING THE ACCOUNTS OF THE 78 SURVIVORS REVEAL HOW THE HEAT RAYS AND SHOCK WAVES AFFECTED PEOPLE.

IMMEDIATELY AFTER THE BLAST PEOPLE WHO MIRACULOUSLY SURVIVED THE BOMB BLAST THEN FACED A NEW THREAT.

IT STARTED IN THE COLLAPSED WOODEN HOUSES.

FIRES WERE SPREADING RAPIDLY FROM THE DESTROYED HOUSES, CUTTING OFF POTENTIAL ESCAPE ROUTES.

CROWDS OF PEOPLE GATHERED ON THE RIVERBANK TO ESCAPE THE FLAMES SURVIVING STUDENT FROM HONKAWA NATIONAL IMARI KIYOKO, ALSO FLED TO THE RIVER.

KATSUKO, A TEACHER WHO SURVIVED, WAS ALSO THERE THE RIVER WAS NO LONGER A SAFE PLACE.

WHAT WAS HAPPENING AT THE RIVER WE ASKED EXPERTS ON LARGE SCALE FIRES TO ANALYZE THE VICTIMS ACCOUNTS AND CONDUCT AN EXPERIMENT FUEL IS BURNED AS AIR IS BLOWN IN.

OBSERVATIONS ARE MADE FROM A VARIETY OF ANGLES THE EXPERIMENT WAS CONDUCTED UNDER CONDITIONS THAT RECREATED THE WAY THE FIRE’S PROGRESS WAS BLOCKED BY THE RIVER IN HIROSHIMA.

THE FLAMES ARE JUTTING OUT DOWNWIND.

SOON, THEY BEGIN TO SPIRAL UPWARD IN A VORTEX.

A FIRE WHIRL.

THESE FIREWALLS APPEARED REPEATEDLY SOMETIMES THE FLAMES KEPT GOING FOR A LONG TIME TWO HOURS AFTER THE EXPLOSION, FIRES HAD SPREAD UP TO TWO KILOMETERS FROM THE HYPOCENTER.

THEY DEVELOPED INTO A MASSIVE METEOROLOGICAL PHENOMENON THIS PHOTOGRAPH OF A PYROCUMULONIMBUS CLOUD IS SAID TO HAVE BEEN TAKEN FOUR HOURS AFTER THE EXPLOSION.

IT IS ESTIMATED TO HAVE BEEN 16KM TALL.

THIS CLOUD MAY HAVE FURTHER FUELED THE SPREAD OF FIRES ON THE GROUND.

THIS VICIOUS CYCLE INCREASED THE FORCE OF THE FIRE WHIRLS.

THEY BEGAN TO APPROACH THE FINANCIAL DISTRICT, WHERE A RELATIVELY LARGE NUMBER OF PEOPLE HAD BEEN SPARED.

TAKAHASHI.

TADASHI WORKED IN THE FUKOKU BUILDING.

AT THE MOMENT THE BOMB EXPLODED, HE WAS IN THE BASEMENT AND ESCAPED UNHARMED.

BUT WHEN HE TRIED TO LEAVE THE BUILDING, THE FIRES IMPEDED HIS ESCAPE.

HE ENCOUNTERED FIREWALLS THREE TIMES.

FINALLY, A WHIRLWIND OF BLACK SMOKE CREATED A NEW SET OF PROBLEMS.

TAKAHASHI BARELY MANAGED TO HOLD ON TAKAKURA.

AKIKO WAS WORKING IN A BANK.

SHE LATER PAINTED A PICTURE OF WHAT SHE WITNESSED AFTER THE FIRE WHIRLS PAST.

A POSTWAR REPORT REVEALED THAT THE ALLIED FORCES DID NOT ANTICIPATE THAT THE RESULTING FIRES WOULD CAUSE SUCH EXTENSIVE DAMAGE.

IT READS FIRE WAS NOT CONFINED TO JAPANESE HOUSES, BUT RAGED FIERCELY IN MANY CONCRETE BUILDINGS.

A SERIOUS NEW PROBLEM IS CREATED BY THE RISKS OF FIRE, WHICH THE BOMB PRODUCES.

SEVERAL DAYS AFTER THE BOMBING, THE 78 SURVIVORS FACED NEW HORRORS ANOTHER THREAT FROM THE ATOMIC BOMB WAS RADIATION.

THE RADIATION RELEASED AT THE MOMENT OF DETONATION, ALONG WITH THE RESIDUAL RADIATION IN THE SOIL.

AND THE RAIN WAS EATING AWAY AT THEIR BODIES.

AFTER THE WAR, RESEARCHERS AT HIROSHIMA UNIVERSITY ESTIMATED THAT THE 78 GROUND ZERO SURVIVORS WERE EXPOSED TO BETWEEN 1 AND 6 SIEVERTS.

EXPERTS SAY THAT HALF THE PEOPLE EXPOSED TO THREE SIEVERTS OF RADIATION WILL DIE.

THE LEVELS OF RADIATION EACH WAS EXPOSED TO WERE CLOSE TO THE LIMIT OF WHAT PEOPLE CAN ENDURE.

MANY OF THOSE WHO’D MANAGED TO SURVIVE WOULD EVENTUALLY SUCCUMB TO THE EFFECTS OF RADIATION EXPOSURE THAT YEAR ALONE.

IT CLAIMED THE LIVES OF SOME 140,000 PEOPLE.

THE MORTALITY RATE FOR PEOPLE WHO WERE AT GROUND ZERO WAS 98.4%.

WHAT THE 78 SURVIVORS EXPERIENCED HERE LEFT DEEP EMOTIONAL SCARS >> KIRISHIMA SAYS.

>> KAWABUCHI KAZUO WAS A HIGH SCHOOL TEACHER.

HE WAS LEADING A GROUP OF 20 GIRLS WHO WERE ON A WORK ASSIGNMENT.

NONE OF THE STUDENTS SURVIVED.

AS A DOCTOR, KAMADA.

NANAO HAS BEEN WATCHING OVER THE 78 SURVIVORS FOR MORE THAN HALF A CENTURY.

BY BUILDING TRUST WITH EACH PERSON AND GAINING THEIR COOPERATION, KAMADA WAS ABLE TO UNCOVER MANY OF THE ILLNESSES CAUSED BY ATOMIC BOMB RADIATION.

ONE PERSON HAS MADE A PARTICULARLY STRONG IMPRESSION.

KIYOKO, THE ONLY STUDENT AT HONKAWA NATIONAL SCHOOL WHO SURVIVED.

HER ESTIMATED RADIATION EXPOSURE WAS FIVE SIEVERTS.

IT WOULDN’T HAVE BEEN SURPRISING IF SHE HAD DIED SOON AFTER AUGUST 6th.

SHE HAD LOST HER ENTIRE FAMILY IN THE ATOMIC BOMBING SHE WAS IN HER 30s WHEN SHE MET HIRO TERU, AND THE TWO WERE MARRIED BUT HER HAPPINESS WAS FLEETING SHE DEVELOPED A SERIES OF ILLNESSES, INCLUDING THYROIDITIS.

SHE HAD TO BE HOSPITALIZED AND UNDERGO SURGERY.

IN HER 60s, SHE DEVELOPED THREE TUMORS IN HER COLON, BRAIN AND NERVES IN HER BACK.

HER CASE WAS UNIQUE, SINCE THE CANCERS DID NOT METASTASIZE, BUT DEVELOPED SEPARATELY IN DIFFERENT LOCATIONS OF THE 78 SURVIVORS, EIGHT DEVELOPED MULTIPLE PRIMARY CANCERS.

THROUGH A LIFETIME OF RESEARCH, KAMADA FOUND THAT PEOPLE WHO WERE EXPOSED TO RADIATION IN CLOSE PROXIMITY WERE MORE LIKELY TO DEVELOP SUCH CANCERS.

>> MITAMURA TARO >> KIYOKO DIED IN 2016 AT AGE 82 JUST BEFORE SHE DIED, KIYOKO REQUESTED THAT HER BODY BE USED TO DEVELOP MEDICAL CARE FOR ATOMIC BOMB SURVIVORS AN AUTOPSY REVEALED A FOURTH TUMOR IN HER LUNG.

OF THE 78 SURVIVORS WHO LIVED THROUGH THE POSTWAR PERIOD, ONLY ONE IS ALIVE TODAY.

TOMODA TSUNEHIRO IS 89.

HE WAS AT HIS SCHOOL, 460M FROM THE HYPOCENTER.

HE LOST HIS ENTIRE FAMILY TOMODA IS VISITING HIS OLD ELEMENTARY SCHOOL.

HE WANTS TO SHARE WHAT HE EXPERIENCED AT GROUND ZERO WITH OTHERS.

AS LONG AS HE IS ABLE TO.

THE MESSAGES LEFT BY THE 78 SURVIVORS ARE BEING PASSED ON TO THEIR FAMILIES.

KAMEDA VISITS THE FAMILY OF TOKUKO HIROKO, WHO WAS COVERED IN GLASS.

HE SHOWS THEM SOME MATERIALS FOR THE FIRST TIME.

THE X-RAY SHOWS THE SHARD OF GLASS AFTER THE WAR, SHE RAN A RESTAURANT AND RAISED TWO DAUGHTERS.

>> NO MORE.

>> 40 YEARS AGO, WHEN LIFE HAD FINALLY BECOME STABLE.

TOKUKO SPOKE ABOUT HER HOPES FOR HER FAMILY.

>> THE 78 SURVIVORS OF GROUND ZERO HAD THE HORRIFIC HUMAN DESTRUCTION OF THE ATOMIC BOMB SEARED INTO THEIR MEMORIES.

BUT AS THE RACE TO DEVELOP NUCLEAR ARMS CONTINUES TO ESCALATE, THEIR VOICES ARE DIRECTED AT OUR WORLD.