Original subtitles

IN THE HEART OF KENTUCKY BOURBON COUNTRY,

BELOW ONE OF LOUISVILLE'S ELITE HOTELS,

LIES A SERIES OF FORGOTTEN TUNNELS.

WAS THIS THE SECRET ESCAPE ROUTE OF NOTORIOUS GANGSTER AL CAPONE?

I THINK WE FOUND SOMETHING IN HERE.

I'LL DEPLOY STATE-OF-THE-ART TECHNOLOGY

TO PEER BENEATH THE FLOORBOARDS

AND PICK UP HIS TRAIL.

AND, IN WESTERN WASHINGTON, A BIZARRE LANDSCAPE

HAS BEEN BAFFLING SCIENTISTS FOR CENTURIES.

WHO OR WHAT BUILT THE MYSTERIOUS MIMA MOUNDS?

OKAY, HERE WE GO.

NOW, AN ADVANCED SCANNING PROCESS

WILL TURN THEM INSIDE OUT

AND COULD LEAD TO A STARTLING REVELATION.

HIDDEN JUST BELOW THE EARTH'S SURFACE,

THERE ARE COUNTLESS UNSOLVED MYSTERIES.

AND, TODAY, WE FINALLY HAVE THE TOOLS TO UNLOCK THEM.

LOOK AT THAT!WHOA.

I THINK THIS IS IT.

I'M ROB NELSON,

A SCIENTIST USING STATE-OF-THE-ART TECHNOLOGY

TO PEEL THE LID OFF OUR PLANET'S HIDDEN DEPTHS.

THE MOMENT OF TRUTH RIGHT HERE.

HOLY MOLY!

THESE ARE THE SECRETS OF THE UNDERGROUND.

Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

LOUISVILLE, KENTUCKY, KNOWN FOR ITS BOURBON,

BATS AND THE FASTEST 2 MINUTES IN SPORTS.

BUT THIS SOUTHERN JEWEL OF THE BLUEGRASS STATE

MAY BE HIDING A DARK SECRET.

THIS BIRTHPLACE OF AMERICA'S ONLY NATIVE WHISKEY

WAS A KNOWN BUSINESS HUB

FOR NOTORIOUS BOOTLEGGER AL CAPONE.

AND EVERYONE KNEW IT, INCLUDING THE POLICE.

YET, FOR NEARLY A DECADE,

HE CONDUCTED HIS ILLICIT BOOZE TRADE

WITHOUT EVER BEING CAUGHT IN THE ACT.

WHENEVER ONE OF HIS PREFERRED HANGOUTS WAS RAIDED,

THE MOB BOSS WAS ALWAYS ONE STEP AHEAD.

WITNESSES CLAIMED HE'D BE THERE ONE MINUTE,

THEN GONE THE NEXT WITHOUT A TRACE.

SO HOW DID CAPONE CONTINUE HIS ILLEGAL OPERATION

FOR OVER A DECADE WITHOUT EVER GETTING CAUGHT?

LEGEND SAYS THE ANSWER MAY LIE

UNDERNEATH THE CITY OF LOUISVILLE.

THERE IS RUMORED TO BE A SECRET NETWORK

OF TUNNELS CARVED DEEP BELOW THE SKYSCRAPERS

AND CITY STREETS THAT CONNECT SEVERAL DOWNTOWN BUILDINGS

WITH AN ALLEGED MAFIA ESCAPE ROUTE TO THE OHIO RIVER.

DURING PROHIBITION, THE UNDERGROUND NETWORK

IS BELIEVED TO HAVE PLAYED A KEY ROLE

IN CAPONE'S BOOTLEGGING BUSINESS.

THE QUESTION IS, DO THESE RUMORED TUNNELS REALLY EXIST?

AND, IF SO, COULD CAPONE HAVE ACCESSED THEM

TO ESCAPE AUTHORITIES

AND PEDDLE HIS ILLEGAL BOOZE?

MY INVESTIGATION STARTS AT BIG AL'S FAVORITE POKER SPOT

AND THE CENTRAL FOCUS OF TUNNEL RUMORS,

THE HISTORIC SEELBACH HOTEL.

OPENED IN 1905,

THIS DOWNTOWN HOT SPOT'S OLD-WORLD GRANDEUR QUICKLY

MADE IT THE PLACE TO SEE AND BE SEEN.

NOTABLE GUESTS INCLUDED FDR, JFK AND THE ROLLING STONES.

F. SCOTT FITZGERALD USED

THE SEELBACH AS INSPIRATION IN HIS CLASSIC NOVEL

"THE GREAT GATSBY."

THE TITLE CHARACTER WAS BASED ON THE REAL-LIFE GANGSTERS

HE SAW HERE, LIKE AL CAPONE,

WHO WAS BUSY MAKING HIS MARK

ON THE BOURBON CAPITAL OF THE WORLD.

IN THE PROHIBITION ERA OF THE 1920s,

EASTERN KENTUCKY SUPPLIED

MUCH OF THE NATION WITH ILLEGAL ALCOHOL.

AFTER PICKING UP A NEW SUPPLY OF BOURBON AND MOONSHINE,

IT WAS SAID CAPONE AND HIS CRONIES

WOULD MEET AT THE SEELBACH TO CONDUCT BUSINESS.

FROM HERE, CASH AND CONTRABAND

WERE ALLEGEDLY FUNNELED UNDERGROUND,

OUT OF SIGHT FROM THE POLICE, AND ACROSS THE COUNTRY.

THIS IS THE LEGEND.

BUT DID IT REALLY HAPPEN?

I NEED TO SEE THESE RUMORED TUNNELS MYSELF.

HI! WELCOME TO THE SEELBACH.

- ROB NELSON. - HI, NICE TO MEET YOU.

- NICE HOTEL. - THANK YOU VERY MUCH.

SO I JOURNEY WITH HOTEL REPRESENTATIVE JIM MEYER

TWO FLOORS BELOW THE LOBBY TO THE HOTEL'S SUB-BASEMENT,

WHERE THEY'RE SAID TO BE LOCATED.

TWO TUNNELS DOWN HERE.

WHOA! LOOK AT THAT!

AND THEN THERE'S A SECOND TUNNEL...

- OH, YEAH. - ...ON THIS SIDE.

THIS IS AWESOME.

LOOKS LIKE A GREAT PLACE TO ESCAPE AS A GANGSTER.

- YEAH. - SMUGGLE YOUR BOOZE.

HAVE YOU BEEN IN HERE?

I HAVE LOOKED AROUND THE CORNER.

THAT'S AS FAR AS I WANTED TO GO.

WHEN THE HOTEL WAS FIRST CONSTRUCTED,

THESE TUNNELS WERE BUILT TO FLUSH OUT RAINWATER

FROM THE BASEMENT.

SO THEY COULD'VE CONNECTED TO A CITY-WIDE

SEWER SYSTEM THAT WOULD'VE OFFERED

CAPONE AN ESCAPE TO JUST ABOUT ANYWHERE.

WHAT I LOVE ABOUT THESE UNDERGROUND BASEMENTS

IS YOU NEVER KNOW WHAT YOU'RE GONNA FIND.

AND YOU'RE KIND OF LOOKING INTO THE--

THE SECRET HISTORY OF THE BUILDING.

I CAN GUARANTEE, YOU'LL NEVER KNOW

WHAT YOU'RE GONNA FIND BACK THERE.

ALL RIGHT. THANK YOU, JIM.

CAN I-- CAN I JUST EXPLORE IT FROM HERE?

- ABSOLUTELY. - OKAY.

- GOOD LUCK. - THANK YOU.

I'M GONNA TAKE THE GoPro BACK INTO THIS TUNNEL,

TRY TO FIGURE OUT IF IT LEADS ANYWHERE.

SAFETY FIRST, THOUGH.

PUT MY MASK ON.

THIS IS EXCITING. ALL RIGHT.

I'M GONNA TAKE YOU DOWN DEEP INTO THE TUNNEL.

CHECK THIS OUT.

I MAKE MY WAY DOWN THE NARROW TUNNEL.

THIS IS NOT SOMETHING

THAT THE AVERAGE TOURIST GETS TO SEE.

BUT I QUICKLY COME TO WHAT APPEARS

TO BE A DEAD END

WITH TWO BLOCKED ENTRANCES.

THERE'S TWO PASSAGEWAYS,

ONE THIS WAY AND ONE THIS WAY.

BOTH OF THEM COULD LEAD SOMEWHERE.

HOLD ON.

OH, WOW.

THIS ONE DEFINITELY LEADS SOMEWHERE.

AND IT KEEPS GOING.

I CAN HEAR RIGHT NOW, I CAN FEEL AIR COMING THROUGH.

SO THE RUMOR THAT AL CAPONE CAME IN HERE,

HID HIS MONEY, HID HIS BOOZE,

COULD VERY WELL BE TRUE.

BUT, TO CONFIRM THESE TUNNELS REALLY KEEP GOING,

I NEED TO USE SOME OF THE TECH I BROUGHT WITH ME.

FIRST UP, THE GROUND-PENETRATING RADAR DEVICE.

THE GPR WILL EMIT A PULSE OF ELECTROMAGNETIC

ENERGY INTO THE WALL.

THE PULSE WILL BOUNCE BACK TO A RECEIVER.

AND THE SPEED AND STRENGTH OF ITS RETURN DETERMINES

THE WALL'S DENSITY AND THICKNESS.

AND, ALMOST IMMEDIATELY, THE GPR OFFERS SOLID CLUES

ABOUT WHAT'S BEHIND THIS WALL.

SO YOU CAN SEE, CLEAR AS DAY,

THERE'S REINFORCEMENT, 3 TO 6 INCHES.

YOU CAN SEE THERE'S REBAR IN THERE.

THE ANOMALIES IN THE DATA

REVEAL NOT ONLY WHAT'S INSIDE THE WALL

BUT WHAT'S BEHIND IT...

NOTHING.

YOU CAN ALSO SEE THAT THERE'S ESSENTIALLY A GAP

AFTER 9 INCHES.

SO IT LOOKS TO ME THAT THIS WALL

IS ABOUT 9 INCHES THICK.

AND NOW FOR THE SECOND POTENTIAL OPENING.

OKAY. I'M GONNA RUN IT ON THE INNER WALL.

OH, YEAH. THERE WE GO.

THIS IS A VERY, VERY THIN WALL.

THIS IS ONLY, LIKE, 2 INCHES THICK.

THERE'S NOTHING BEHIND IT.

IF, IN THEORY, WE COULD GET THROUGH THIS WALL,

I THINK WE COULD GET TO A WHOLE TUNNEL NETWORK.

GPR CONFIRMS IT.

THERE'S EMPTY SPACE BEHIND THESE TWO PORTALS.

THAT MEANS THAT, IF CAPONE ESCAPED THROUGH

THESE SEWER TUNNELS,

HE COULD'VE CHOSEN TO GO EITHER DIRECTION,

FURTHER CONFUSING ANYONE ATTEMPTING TO PURSUE HIM.

SO ALL HE HAD TO DO WAS WALK DOWN HERE

FROM THE LOBBY LIKE I DID,

AND HE'D BE HOME FREE, RIGHT?

ACCORDING TO THE LEGENDS, NOT EXACTLY.

WHILE CAPONE MAY HAVE LIKED DOING HIS BUSINESS

AT THE SEELBACH BECAUSE OF ITS PROXIMITY

TO THE TUNNEL SYSTEM,

HE COULDN'T JUST MEET HIS ASSOCIATES IN THE LOBBY

EXCHANGING SUITCASES OF CASH.

SO HE PREFERRED TO MEET IN THE GENTLEMEN'S POKER ROOM,

WHICH WAS MORE PRIVATE.

BUT IT WAS ALSO ON THE 2nd FLOOR

WITH NO DIRECT ACCESS TO THE SUB-BASEMENT.

OR WAS THERE?

IF THE POLICE RAIDED THE HOTEL LOOKING FOR CAPONE,

WHICH THEY OFTEN DID,

HOW COULD HE HAVE MADE HIS WAY DOWN THREE FLIGHTS

WITHOUT BEING SEEN?

I THINK THIS HOTEL MAY BE HIDING EVEN MORE

THAN ITS UNDERGROUND TUNNEL SYSTEM.

COULD THERE ALSO BE A SECRET STAIRCASE

CONNECTING THE POKER ROOM TO THE BASEMENT?

TO TRACE THE ESCAPE ROUTE OF AL CAPONE,

I'M GOING TO NEED SOME HIGH-TECH TOYS.

JUST TURN IT ON AND RUN IT.

OH, WOW. LOOK AT THAT!

AND, LATER, I'LL DEPLOY ANOTHER SET OF GADGETS

TO PROBE WASHINGTON'S OTHERWORLDLY MIMA MOUNDS.

THIS IS UNBELIEVABLE.

ARE THEY THE WORK OF ANCIENT HUMANS,

THE EARTH ITSELF OR SOMETHING EVEN MORE UNBELIEVABLE?

OKAY, SO LET ME JUST GET THIS STRAIGHT.

I'M IN LOUISVILLE, KENTUCKY, ON THE HUNT

FOR AL CAPONE'S SECRET ESCAPE ROUTE.

I UNCOVERED A PAIR OF TUNNELS

IN THE BASEMENT OF CAPONE'S FAVORITE LOCAL HOTEL,

THE SEELBACH, THAT APPEAR TO LEAD AWAY FROM THE BUILDING.

BUT TO UNDERSTAND HOW HE COULD'VE ACCESSED THEM,

I NEED TO LEARN MORE ABOUT THE SEELBACH'S STORIED PAST.

SO I ARRANGE A MEETING WITH HISTORIAN

AND FORMER SEELBACH EMPLOYEE LARRY JOHNSON.

THIS IS THE GENTLEMEN'S POKER ROOM.

SO I'VE HEARD THE LEGENDS

THAT, WHEN AL CAPONE WAS HERE,

HE USED SOME SORT OF, UH,

ESCAPE DOOR TO ESCAPE, YOU KNOW, THE POLICE.

YOU KNOW, IF HE WAS HERE IN THIS ROOM,

THEN HOW WOULD HE DO THAT?

AT THE TIME, THE HOTEL WAS OWNED BY A GENTLEMAN

BY THE NAME OF ABRAHAM LIEBLING FROM CHICAGO.

SO THERE WERE CHICAGO TIES.

THEY WOULD, UH, MAKE SURE THAT THE HOTEL

WAS SECURE FOR THEM WHEN THEY WERE HERE.

IF THE POLICE CAME IN DOWNSTAIRS,

THERE WAS A BUTTON EITHER AT THE FRONT DESK

OR IN THE BELL STAND.

SOMEBODY WOULD PUSH THE BUTTON.

THESE DOORS WERE SPRING-LOADED.

AND THEY WOULD AUTOMATICALLY CLOSE.

AND THAT TOLD THE GENTLEMEN

THAT IT WAS TIME FOR THEM TO LEAVE.

SO IT WOULD SPRING SHUT?

IT WOULD SPRING SHUT

AND LOOK LIKE A WALL FROM THE OTHER SIDE.

AND, FROM THE OUTSIDE, YOU WOULDN'T EVEN KNOW

THAT THIS ROOM EVEN EXISTED.

AND, OF COURSE, YOU'D NEED AN ESCAPE OUT OF THIS ROOM.

BASICALLY, THIS WHOLE STORY STARTS FROM THIS ROOM.

SEALING THE DOORS COULD BUY CAPONE SOME TIME.

BUT HE STILL NEEDED AN ESCAPE ROUTE IN CASE

THE COPS DISCOVERED THE POKER ROOM.

SO HOW DID HE GET OUT?

LOOKING AROUND THE ROOM,

THERE DON'T APPEAR TO BE ANY OBVIOUS EXITS.

BUT THEN I COME ACROSS SOMETHING PECULIAR.

THIS PANEL IN THE WALL LOOKS LIKE A SEALED DOOR

AND SOUNDS HOLLOW WHEN I KNOCK ON IT.

IN, UH, 1981, THERE WAS A FIRE

THAT BURNED OUT THE DOOR.

SO THEY WERE NO LONGER OPERATIONAL.

COULD CONSTRUCTION FROM THE REPAIRS

HAVE COVERED UP AL CAPONE'S SECRET PASSAGEWAY?

SINCE WE CAN'T JUST TEAR OPEN THE WALL,

THERE'S ONLY ONE WAY TO FIND OUT FOR SURE.

I'M GONNA GET SOME OF MY TECH GUYS UP HERE

TO SCAN THE ROOM AND PIECE TOGETHER THIS MYSTERY.

I'M BRINGING IN BRAD RISTER AND HIS TEAM OF EXPERTS

FROM GPR ENGINEERING TO HELP ME HUNT

FOR THE POKER ROOM'S HIDDEN SECRETS.

- THANKS FOR COMING. - ABSOLUTELY.

- GOOD TO SEE YOU. - GOOD TO SEE YOU.

THE FIRST PIECE OF TECH WE'LL USE IS A LiDAR MACHINE,

WHICH STANDS FOR LIGHT DETECTION AND RANGING.

THIS THING IS GONNA SPIN AROUND,

SHOOT A WHOLE BUNCH OF LASERS,

WHICH IS GONNA GIVE US A RELIEF PICTURE OF THIS ROOM.

SO, HOPEFULLY, IF THERE WAS A SECRET PASSAGEWAY,

WE'LL BE ABLE TO FIND IT.

LiDAR USES THE LIGHT FROM LASERS

TO CREATE 3-DIMENSIONAL RENDERINGS

THAT CAN THEN BE ANALYZED WITH PRECISION

DOWN TO THE SMALLEST DETAILS.

IT CAN ALSO BE USED ON A MACRO SCALE,

LIKE IN 2015,

WHEN AERIAL REMOTE-SENSING LiDAR

WAS USED TO DISCOVER A MYSTERIOUS CULTURE'S LOST CITY

IN THE HONDURAN RAINFOREST.

TODAY, THOUGH, WE'LL USE IT

TO SCAN CAPONE'S 2nd-FLOOR HIDEOUT,

INCLUDING THE POKER ROOM AND HALLWAYS SURROUNDING IT,

TO GIVE US A MORE ACCURATE PICTURE

OF THE ENTIRE SPACE

AND EXPOSE ANY ANOMALIES UNDER FLOORS

AND BEHIND WALLS THAT COULD UNCOVER

REMNANTS OF CAPONE'S HIDDEN STAIRCASE.

LET'S TURN IT ON AND RUN IT.

THE LASERS FROM THE LiDAR COULD DAMAGE OUR CAMERAS.

SO WE CAN'T FILM THE PROCESS.

BUT I CAN'T WAIT TO SEE WHAT THE DATA REVEALS.

OKAY. SO I HAVE OUR RESULTS

OF OUR LiDAR TEST RIGHT HERE.

WE'LL SEE IF WE CAN FIND ANY ANOMALIES.

THE DATA GIVES ME A 3-D MODEL OF THE ENTIRE ROOM.

OKAY, SO HERE'S THE ENTRANCE TO THE POKER ROOM.

THE TABLE, CHANDELIER AND EVEN THE CARPET PATTERN

ARE CLEAR AS DAY.

ANYTHING THAT'S STRANGE OR OUT OF PLACE

WILL SHOW UP IN THE LiDAR IMAGE.

AND WHAT I'M MOST INTERESTED IN IS THE AREA

NEAR THAT SEALED DOOR I FOUND.

OH, WOW. LOOK AT THAT.

IF YOU LOOK AT THIS, YEAH,

RIGHT HERE BEHIND THE POKER ROOM,

THERE'S A LITTLE INDENTATION IN THE FLOOR,

LIKE SOMEBODY WAS TRYING TO COVER SOMETHING UP OR,

UM, MAYBE FILL SOMETHING IN.

ESSENTIALLY, WHAT IT'S DOING IS IT'S ALLOWING US

TO NOW PINPOINT OUR INVESTIGATION RIGHT HERE.

SO WHAT I'LL DO IS I'LL GRAB BRAD.

I'LL GRAB THE GUYS. WE'LL SCAN THIS AREA

AND SEE IF THERE'S ANY HIDDEN SECRETS BELOW.

THE LiDAR REVEALED EXACTLY

WHERE I NEED TO SEARCH FOR EVIDENCE

OF CAPONE'S HIDDEN ESCAPE HATCH,

MOST LIKELY A SMALL STAIRCASE LEADING DOWN.

THERE IS AN INDENTATION HERE.

THE NEXT STEP IS TO DETERMINE WHAT LIES BENEATH IT

BY USING GROUND-PENETRATING RADAR.

I'M GONNA RUN A VERTICAL STRIPE FROM HERE OVER.

HOLY CRAP!

COULD THAT BE A STAIR?

YOU DO HAVE SOME TYPE OF ANOMALY DOWN HERE,

UH, ABOUT 7 1/2 INCHES.

OUR GPR DATA HAS REVEALED SOME CURIOUS IRREGULARITIES

IN THE MATERIALS BENEATH THIS FLOOR.

THEY COULD'VE REMODELED AND COVERED THIS BACK OVER.

WHAT I INTERPRET OUT OF THE DATA

THAT YOU JUST SCANNED,

THAT THE FLOOR IS DISCONTINUOUS ON HOW IT'S BUILT.

SO, IF IT WAS BUILT ORIGINAL AT A CERTAIN THICKNESS,

THEN ALL THIS DATA WOULD LOOK THE SAME.

IT'S GOT MULTIPLE LAYERS OF SOME TYPE OF MATERIAL.

SO YOU CAN'T TELL IF THERE'S A STAIRCASE.

BUT YOU CAN TELL THAT THIS PROBABLY

WAS NOT THE ORIGINAL FLOOR.

THAT'S NOT THE ORIGINAL FLOOR, RIGHT.

IT SEEMS CLEAR THAT, AT SOME POINT,

THIS PART OF THE HOTEL WAS RECONSTRUCTED,

PERHAPS INADVERTENTLY COVERING UP CAPONE'S INFAMOUS TRACKS.

WHEN IT CAME TO THE ART OF ELUDING CAPTURE,

BIG AL WAS THE BEST IN THE BUSINESS.

AT THE FAMOUS GREEN MILL COCKTAIL LOUNGE

BACK IN HIS NATIVE CHICAGO,

HE HAD A REGULAR BOOTH WITH CLEAR VIEWS

OF BOTH THE FRONT AND BACK ENTRANCES.

IT WAS SAID THAT, WHEN COPS RAIDED THE JOINT,

CAPONE DISAPPEARED DOWN A SECRET HATCH BEHIND THE BAR

THAT LED TO A NETWORK OF OLD COAL TUNNELS BELOW.

FROM THERE, HE COULD SLIP INTO VARIOUS BUILDINGS

CONNECTED TO THE TUNNELS

AND STAY ONE STEP AHEAD OF THE POLICE.

IT MAY SOUND LIKE THE STUFF OF HOLLYWOOD MOVIES.

BUT CRAFTY CRIMINALS HAVE BEEN USING TUNNELS

TO ESCAPE AS LONG AS AUTHORITIES HAVE BEEN CHASING THEM.

SINCE ANCIENT TIMES, CATACOMBS IN ROME

AND PARIS HAVE OFFERED OUTLAWS

AND REBELS AN EASY REFUGE FROM THE LAW.

AND, EVEN IN OUR TIME,

INFAMOUS MEXICAN DRUG LORD "EL CHAPO" GUZMáN

TOOK A PAGE FROM CAPONE'S PLAYBOOK

WHEN HE CONSTRUCTED SEVEN SAFE HOUSES

IN THE MEXICAN CITY OF CULIACáN.

LOOKS LIKE A BATHTUB, RIGHT? CHECK THIS OUT.

EACH MODEST-LOOKING HOME HAD A BATHTUB EQUIPPED

WITH A SECRET TUNNEL BELOW IT.

THE TUNNELS WOULD LINK UP WITH THE PUBLIC SEWAGE SYSTEM,

WHERE GUZMáN COULD TRUDGE THROUGH UNDERGROUND SLUDGE

FOR UPWARDS OF 2 MILES

BEFORE RESURFACING UNDER A BATHTUB

IN A DIFFERENT SAFE HOUSE,

EFFECTIVELY ALLOWING HIM TO ELUDE POLICE FOR YEARS.

IN 2013, THE CHICAGO CRIME COMMISSION NAMED

GUZMáN PUBLIC ENEMY NUMBER ONE.

AND THE FIRST PERSON EVER TO RECEIVE

THAT TITLE, AL CAPONE.

THIS SECTION OF THIS ROOM

VERY WELL COULD'VE BEEN THE STAIRWAY.

THIS IS A HUGE DISCOVERY BECAUSE THIS COULD BE

THE HIDDEN PASSAGEWAY OF AL CAPONE.

NOBODY HAS ACTUALLY COME IN

AND DETECTED THESE ANOMALIES YET.

- MM-HMM. - THERE-- THERE'S RUMORS

THAT THESE EXISTED.

WE KNOW NOW THAT THE FLOOR IS DIFFERENT HERE.

HE HAD TO HAVE FOUND A WAY TO GET TO THE BASEMENT.

WE HAVE TO FIGURE OUT WHAT'S BELOW THIS...

MM-HMM.

...AND KIND OF DO IT ALL IN REVERSE...

- AND WORK IT BACKWARDS, SURE. - ...AND WORK IT BACKWARDS.

NOW I WANT TO TRACE THIS SHAFT DOWN INTO THE BASEMENT.

SO I ASK SEELBACH HISTORIAN LARRY JOHNSON TO SHOW ME

WHAT'S DIRECTLY UNDER THE POKER ROOM.

TWO FLIGHTS STRAIGHT DOWN LIES

ONE OF THE MOST ICONIC ROOMS

IN THE SEELBACH AND ONE THAT CAPONE

AND HIS CRONIES WOULD'VE KNOWN QUITE WELL.

HOLY MOLY!

THIS IS AN AWESOME ROOM.

THIS IS THE RATHSKELLER.

FUN FACT, "RATHSKELLER" IS A GERMAN WORD

FOR A SUBTERRANEAN BEER HALL.

F. SCOTT FITZGERALD WAS ACTUALLY

KICKED OUT OF THE ROOM FOR BEING A DRUNK.

AND, ON ONE OCCASION, HE WAS SITTING AT THE BAR.

AND HE SPOTTED AL CAPONE AND GEORGE REMUS.

AND THAT'S WHERE HE STARTED WRITING "THE GREAT GATSBY."

- OH, REALLY? - HE'D WRITE DOWN NOTES

ON COCKTAIL NAPKINS ABOUT HOW THE PEOPLE REACTED.

SO AL CAPONE WOULD'VE COME DOWN THROUGH HERE, IN THEORY?

YES.

OUR PURSUIT OF CAPONE'S ESCAPE ROUTE

TAKES US INTO AN OLD WINE CELLAR

WHICH LINES UP EXACTLY

WITH THE STAIRCASE SHAFT WE DETECTED.

SO, RIGHT NOW, WE'RE UNDERNEATH THE POKER ROOM?

WE'RE ACTUALLY 1 1/2 FLOORS UNDERGROUND.

AND THE POKER ROOM IS STRAIGHT UP

FROM THIS SHAFT RIGHT HERE.

HOLY CRAP.

LARRY, HAVE YOU SEEN THIS? IF YOU LOOK RIGHT HERE,

YOU CAN SEE THE WOOD STEPS ON THE BOTTOM...

- OH, YEAH. - ...AND RIGHT THERE.

AND THERE'S, LIKE, A LITTLE BIT OF A COVE

KIND OF DUG OUT.

HERE WAS THE OLD MATERIAL. THAT'S UNDERNEATH THE STAIRS.

- YEAH. - SO THAT WOULDN'T HAVE BEEN

WHERE THE STAIRCASE WOULD'VE BEEN.

IT WOULD'VE HAD TO HAVE BEEN FROM ABOUT THERE OVER,

WHICH MEANS THAT IT WOULD'VE ONLY BEEN ABOUT THAT WIDE.

YEAH.

IT WOULD'VE BEEN A VERY NARROW STAIRCASE.

WAS THAT BEFORE YOU WERE HERE? DID YOU EVER SEE THE STAIRS?

I NEVER SAW THE STAIRS.

THIS IS THE FIRST TIME I'VE BEEN IN THIS ROOM.

IT'S LIKE WE'RE FIGURING OUT THIS MYSTERY AS WE GO.

- YEAH, AS WE GO. - OH, WOW, LOOK AT THAT.

HAVE YOU-- DID YOU NOTICE THAT?

I'VE NEVER SEEN THAT HOLE BEFORE.

WHOA!

LET ME CRAWL UP THERE A LITTLE BIT.

WE'RE IN THE SEELBACH HOTEL IN LOUISVILLE, KENTUCKY,

ON THE TRAIL OF WHAT MAY HAVE BEEN

AL CAPONE'S LEGENDARY ESCAPE ROUTE,

A VERTICAL SHAFT FROM THE 2nd-FLOOR POKER ROOM

INTO THE SUB-BASEMENT.

THERE'S, LIKE, A LITTLE GAP.

IT'S NOT VERY BIG, MAYBE 2 FEET.

I THINK YOU COULD SQUEEZE THROUGH IT, THOUGH.

THIS IS FRICKING COOL.

I'M GONNA TAKE THE GoPro, PUT IT UP THERE

SO YOU GUYS CAN SEE WHAT IT LOOKS LIKE.

UH, ALL RIGHT.

WE'RE GOING UP INSIDE--

INSIDE THE CEILING FROM THE DOWNSTAIRS,

UP, UP, UP, UP, UP, UP.

AND THERE WE GO. IT'S A SUPER TIGHT GAP.

AL CAPONE WAS NO FEATHERWEIGHT.

HE WAS SAID TO STAND AROUND 5'10"

AND WEIGH AS MUCH AS 250 POUNDS.

IT WOULD'VE BEEN ESPECIALLY TIGHT

FOR SOMEONE THE SIZE OF CAPONE.

BUT IT'S POSSIBLE HE COULD'VE SQUEEZED THROUGH HERE.

WE'VE GOT THE STAIRS RIGHT THERE AND THIS--

THIS IS THE WALL ON THE OTHER SIDE.

SO WE'RE TALKING MAYBE 2 FEET IN BETWEEN.

BUT I THINK A STAIRCASE COULD'VE BEEN IN THERE.

WHAT I'M LOOKING FOR IS SOME SORT OF SIGNS OF A FIRE.

THAT-- THAT BLACK RIGHT THERE,

THAT LOOKS PRETTY PROMISING TO ME.

IN 1981, A FIRE DESTROYED THIS SECTION OF THE SEELBACH.

SO, IF THERE REALLY WAS A STAIRCASE HERE,

IT WOULD'VE GONE UP IN FLAMES.

BUT THE SHAFT ITSELF PREDATES THE FIRE.

COME HERE AND LOOK AT THIS.

OKAY. THAT'S WHAT WE'RE TALKING ABOUT.

ALL THAT'S BEEN REDONE. YOU SEE THAT BLACK THERE?

THAT COULD'VE BEEN FROM THE OLD FIRE.

THERE IS NO EVIDENCE OF A STAIRCASE ANYMORE

EXCEPT FOR A FEW PIECES OF WOOD

THAT I'VE DISCOVERED.

THIS IS EXCITING.

THE BURNED WOOD IS COMPELLING EVIDENCE

THAT A WOODEN STRUCTURE, QUITE POSSIBLY

A WORKING STAIRCASE, ONCE EXISTED HERE.

CAPONE COULD CONCEIVABLY HAVE USED IT TO SLIP DOWN HERE

FROM THE POKER ROOM WITHOUT BEING SEEN.

THESE SECRET STAIRS WOULD'VE LED HIM

ALMOST DIRECTLY TO THE RATHSKELLER,

WHERE HE COULD'VE QUICKLY MADE HIS WAY DOWN

TO THE SUB-BASEMENT AND, FROM THERE,

INTO THE TUNNEL SYSTEM I SAW EARLIER,

WHERE HE'D HAVE HIS CHOICE OF TWO EXIT PATHS LEADING

TO OTHER PARTS OF THE CITY.

THIS HIDDEN ESCAPE ROUTE WOULD'VE ALLOWED CAPONE

TO MOVE FREELY UNDERNEATH LOUISVILLE,

ELUDE CAPTURE FOR YEARS

AND ENABLE HIS ILLEGAL EMPIRE,

WORTH BILLIONS IN TODAY'S MONEY,

TO FLOURISH FOR SO LONG.

SO IT SEEMS THE PARTY CROWD OF THE PROHIBITION ERA

OWES A DEBT OF GRATITUDE

TO THE SEELBACH AND ITS HIDDEN SECRETS.

NOW, FROM THE URBAN UNDERBELLY OF THE HEARTLAND,

I'M HEADING TO THE WILD EXPANSE OF THE WEST COAST.

JUST OUTSIDE OLYMPIA, WASHINGTON, SITS

AN ALMOST OTHERWORLDLY SITE...

...A SPRAWLING PLAIN COVERED BY ROUNDED,

EARTHEN MOUNDS THAT STRETCH FOR 10,000 ACRES.

SOME OF THE MOUNDS STAND OVER 7 FEET TALL.

THESE ARE THE MIMA MOUNDS.

I HAVE NEVER SEEN ANYTHING LIKE THIS.

IN ALL DIRECTIONS,

AS FAR AS THE EYE CAN SEE,

ARE THESE HUGE, HUGE MOUNDS.

ARE THEY MAN-MADE,

SOME SORT OF OBSCURE GEOLOGICAL PHENOMENON

OR SOMETHING EVEN MORE SURPRISING?

SO FAR, NO ONE HAS COME UP WITH A DEFINITIVE ANSWER.

THESE MOUNDS ARE ONE OF THE GREATEST

UNSOLVED MYSTERIES IN ALL OF AMERICAN GEOLOGY.

SO I WANT TO FIGURE OUT WHAT'S GOING ON.

THIS MYSTERIOUS LANDSCAPE IS SO BIZARRE

THAT SOME HAVE EVEN SUGGESTED IT WAS SHAPED BY ANCIENT ALIENS.

THAT MIGHT BE A STRETCH.

BUT HOW ABOUT OTHER SENTIENT BEINGS?

WHEN EARLY EXPLORERS FIRST HAPPENED

UPON THIS SPOT IN 1841,

THEY BELIEVED THE HILLS

WERE ANCIENT NATIVE AMERICAN BURIAL MOUNDS

BECAUSE THEY LOOKED SIMILAR TO OTHERS FOUND ACROSS THE COUNTRY,

JUST ON A MUCH WIDER SCALE.

WHEN THE ADVENTURERS DUG INTO THEM,

THOUGH, THEY FOUND NO BONES OR OTHER RELICS.

SO THE MOUNDS DON'T APPEAR TO BE GRAVE SITES.

BUT COULD THEY BE SOME OTHER KIND OF HUMAN CONSTRUCTION?

WALKING UP, DOWN AND AROUND THESE HILLS,

THEY CERTAINLY REMIND ME OF MAN-MADE EARTHWORKS

I'VE SEEN BEFORE,

LIKE THE CAHOKIA MOUNDS IN ILLINOIS,

WHICH WERE PART OF A THRIVING ANCIENT CITY COMPLETE

WITH A TOWERING CENTRAL PLAZA

OR THE REMNANTS OF RIDGES

AND HILLS THAT MARK PREHISTORIC SETTLEMENTS AT WATSON BRAKE

AND POVERTY POINT IN LOUISIANA

OR EFFIGY MOUNDS SCATTERED AROUND THE COUNTRY,

SOME OF WHICH HELPED CHART THE ALIGNMENT OF PLANETS

AND STARS THAT WERE IMPORTANT TO THE BUILDERS.

SO COULD THERE BE SOME OTHER CEREMONIAL

OR PRACTICAL PURPOSE TO THE MIMA MOUNDS

BEYOND SIMPLE BURIAL SITES?

ARCHAEOLOGICAL EVIDENCE SUGGESTS

THAT HUMANS HAVE BEEN IN THIS AREA

FOR ALMOST 13,000 YEARS.

SO I THINK THAT IF I CAN FIND EVIDENCE

OF SOME CLEAR PATTERN TO THE MOUND PLACEMENT,

THAT COULD SUGGEST THEY'RE MAN-MADE.

IT'S NEARLY IMPOSSIBLE TO SEE

IF THERE'S AN OVERARCHING PATTERN

FROM DOWN HERE ON THE GROUND.

SO WHAT I REALLY NEED IS A BIRD'S-EYE VIEW.

AND THE ONLY WAY TO DO THAT IS TO BREAK OUT MY DRONE.

OKAY, HERE WE GO.

AS THE DRONE SOARS INTO THE SKY ABOVE,

IMAGES START TO COME IN.

AND, AT FIRST GLANCE, THE MOUNDS APPEAR VERY ORDERLY.

YOU KNOW, AS I'M LOOKING AT THIS,

IT LOOKS VERY SYMMETRICAL TO ME.

I ALMOST THINK I'M SEEING A PATTERN.

COULD THIS BE THE EVIDENCE

OF HUMAN INVOLVEMENT I'M LOOKING FOR?

WHOA, LOOK AT THAT!

I'M TRYING TO SOLVE

THE ENDURING MYSTERY OF THE MIMA MOUNDS,

A BIZARRE LANDSCAPE THAT REMINDS ME

OF OTHER MAN-MADE EARTHWORKS

I'VE SEEN AROUND THE COUNTRY

BUT ON A MUCH MORE MIND-BOGGLING SCALE.

SO I'VE LAUNCHED A DRONE TO SEE IF I CAN MAKE OUT

ANY EVIDENCE OF UNNATURAL SHAPES

OR INTENTIONAL PATTERNS

THAT WOULD SUGGEST HUMAN INVOLVEMENT.

AND I MAY BE ONTO SOMETHING.

I ALMOST THINK I'M SEEING A PATTERN.

I MEAN, YOU CAN SEE ALL THESE LITTLE MOUNDS.

AND THEY LOOK SOMEWHAT EVEN. OR DO THEY?

IS IT JUST THAT MY BRAIN

WANTS TO SEE A PATTERN EVEN IF NONE EXISTS?

THAT'S ACTUALLY A PSYCHOLOGICAL PHENOMENON

CALLED PAREIDOLIA.

OUR BRAINS ARE WIRED TO DETECT HUMAN FACES FROM BIRTH

AND TO MAKE SENSE OF THE VISUAL INFORMATION

IN FRONT OF US.

SO, BECAUSE OF THAT, WE SOMETIMES SEE FACES

OR DISTINCT SHAPES IN INANIMATE OBJECTS

LIKE ROCKS OR PLANETS OR EVEN TOAST.

IN FACT, THE LONGER I LOOK AT THE DRONE FOOTAGE,

THE LESS CONVINCED I AM THAT

THERE'S ANY PRECONCEIVED ORDER

OR DESIGN TO THE MOUNDS.

I FEEL LIKE MY MIND

IS SHOWING A PATTERN TO ME THAT MAY NOT EXIST.

I DON'T SEE ANY OF THE HALLMARKS OF MAN-MADE ORIGINS FOUND

IN OTHER NATIVE AMERICAN MOUNDS.

THERE'S NO REPEATING GEOMETRIC PATTERN

OR ANIMAL SHAPES

OR EVEN MORE THAN A COUPLE MOUNDS

THAT LIE IN A STRAIGHT LINE.

THE MOUNDS ARE ALSO ALL DIFFERENT SIZES.

SO, WITHOUT CONVINCING PHYSICAL EVIDENCE TO THE CONTRARY,

LIKE A TRAIL OF MAN-MADE ARTIFACTS IN THE VICINITY,

I'LL HAVE TO CONSIDER OTHER THEORIES

ABOUT THE CREATION OF THE MIMA MOUNDS.

THE MOST LIKELY ALTERNATIVE TO HUMAN CONSTRUCTION

WOULD BE SOME SORT OF GEOLOGICAL PROCESS.

IN FACT, LOOKING AT THE DRONE FOOTAGE,

IT ALMOST SEEMS LIKE SOMETHING PUSHED THE EARTH UP FROM BELOW.

I'M WONDERING IF THE MIMA MOUNDS

MIGHT BE AN EXTREME VERSION OF A PHENOMENON

I'VE SEEN BEFORE CALLED A GILGAI FIELD.

GILGAI ARE REPEATED MOUNDS

AND DEPRESSIONS THAT FORM IN CLAY-RICH SOIL.

CYCLES OF WET AND DRY SEASONS

CAUSE THE GROUND TO SWELL

AND SHRINK AS THE CLAY SUCKS UP WATER

AND THEN DRIES OUT.

OVER TIME, THE SUB-SOIL

IS FORCED UPWARDS TO FORM MOUNDS.

THE ONLY WAY TO KNOW IF THIS IS WHAT I'M SEEING AT MIMA MOUNDS

IS TO GET A BETTER UNDERSTANDING OF THE EARTH BENEATH MY FEET.

IF I CAN FIND CLAY PRESENT IN THE SOIL,

THAT COULD SUGGEST THESE MOUNDS ARE GILGAI.

SO I'M TURNING TO GEOPHYSICIST DR. MIKE FEVES

TO HELP ME DEPLOY A POWERFUL TECHNOLOGY

THAT SHOULD BE ABLE TO DETECT CLAY CONTENT.

IT'S CALLED ELECTRICAL RESISTIVITY TOMOGRAPHY OR E.R.T.

E.R.T. IS AN ADVANCED SUBSURFACE IMAGING TECHNIQUE

THAT ALLOWS US TO SEE HUNDREDS OF FEET BELOW THE SURFACE.

IT WORKS BY INJECTING ELECTRICAL CURRENT

INTO THE GROUND

BETWEEN TWO ELECTRODES AT A TIME.

ADDITIONAL ELECTRODES THEN MEASURE HOW EASILY

THAT CURRENT IS FLOWING THROUGH WHATEVER LIES BELOW.

SINCE THE CONDUCTIVITY OF VARIOUS MATERIALS IS DIFFERENT,

E.R.T. CAN DETERMINE SPECIFIC SOIL ELEMENTS,

FIND WATER TABLES

AND EVEN LOCATE VOIDS IN THE SUBSURFACE.

E.R.T. MADE HEADLINES IN 2016

WHEN IT WAS USED TO UNCOVER A SECRET TUNNEL DUG BY JEWS

ATTEMPTING TO FLEE A NAZI EXECUTION SITE IN LITHUANIA.

AND IT'S A GREAT TOOL FOR OUR INVESTIGATION

INTO WHETHER THE MIMA MOUNDS COULD BE GILGAI.

SINCE CLAY MATERIALS ARE HIGHLY CONDUCTIVE,

SOIL WITH CLAY CONTENT CAN BE EASILY

IDENTIFIED WITH E.R.T. TESTING.

Dr. Feves: WE'RE GONNA PUT A STAKE IN EVERY 4 FEET.

- OKAY. - THAT'S GOOD!

56 METAL ELECTRODES

WILL PASS THE CURRENT INTO THE GROUND.

COOL THING IS THIS HAS NEVER BEEN DONE BEFORE OUT HERE.

COULD FIND SOMETHING NEW.

THERE YOU GO. PERFECT.

WITH THE STAKES IN PLACE, WE RUN OUR CABLE,

WHICH ATTACHES TO EACH ELECTRODE

AND THE DATA ACQUISITION SYSTEM.

- GOOD AND TIGHT. - OKAY.

WELL, I'M HOPING IT SHOWS SOMETHING,

GIVES US SOME SORT OF READING,

SOME SORT OF INDICATION WHAT'S UNDERNEATH HERE.

SO I'LL HIT THE START BUTTON HERE.

AND WE'RE OFF AND RUNNING.

CURRENT STARTS PULSING INTO THE EARTH.

AND DATA STARTS ROLLING IN WITH SOME SURPRISING RESULTS.

THIS GROUND HERE IS REALLY HIGH RESISTIVITY.

SO WHAT DOES THAT-- WHAT DOES THAT MEAN?

WE'RE SEEING RESISTIVITIES HERE OF 150,000 OHM-METERS.

THAT'S LIKE INTACT KIND OF ROCK

THAT YOU REALLY CAN'T GET CURRENT INTO,

WHICH IMPLIES THERE'S NO CLAY CONTENT IN THE--

IN THE-- IN THE SOILS.

AND IT'S VERY DRY.

INSTEAD OF FINDING SOFTER, CLAY-RICH SOIL,

WE'VE DISCOVERED THAT A HARD LAYER OF DRY,

GRANULAR MATERIAL RUNS UNDER THIS ENTIRE AREA,

WHICH MEANS THESE MOUNDS COULDN'T BE GILGAI.

SO WE CAN ELIMINATE THAT THEORY.

BUT NOW I'M WONDERING WHAT OTHER NATURAL FORCES

HAVE THE ABILITY TO RESHAPE THE EARTH?

AND THERE'S ONE IMPORTANT CHARACTERISTIC

OF THIS PART OF THE COUNTRY THAT HAS TO BE CONSIDERED.

IT'S PRONE TO SEISMIC ACTIVITY.

THE MIMA MOUNDS ARE LOCATED WITHIN THE RING OF FIRE,

A GEOLOGICALLY AND VOLCANICALLY ACTIVE AREA

THAT RUNS AROUND THE PACIFIC.

ROUGHLY 90% OF THE WORLD'S EARTHQUAKES

OCCUR ALONG THIS PATH.

SOME SCIENTISTS HAVE SPECULATED THAT THE MIMA MOUNDS

COULD BE THE RESULT OF SEISMIC ACTIVITY,

THAT TECTONIC RUMBLINGS CAUSE THE EARTH'S CRUST

TO RIPPLE AND FORM DISTINCT HILLS.

IN MY RESEARCH, I CAME ACROSS A PRETTY LOW-TECH EXPERIMENT

THAT CAN BE DONE TO TEST THIS THEORY.

AND I WANT TO TRY IT OUT MYSELF.

SO I'M GONNA TAKE THIS HAMMER, WHICH SIMULATES AN EARTHQUAKE.

THE EARTH'S CRUST IS REPRESENTED HERE

BY THE PLYWOOD AND KIND OF THE TOPSOIL

IS REPRESENTED BY THIS THIN SHEET OF SAND.

AND SO LET'S JUST SEE HOW LIKELY IT IS

THAT THESE MOUNDS FORMED THIS WAY.

EACH HAMMER HIT IS MEANT TO REPRESENT A SEISMIC EVENT.

IT'S MAKING THE BOARD SHAKE IN ROUGHLY THE SAME WAY

THE GROUND WOULD DURING AN EARTHQUAKE.

OH, MY GOSH! LOOK AT THAT!

YOU SEE THAT?

THAT-- THAT BASICALLY LOOKS EXACTLY LIKE MIMA MOUNDS.

THIS IS UNBELIEVABLE.

IS A HAMMER AND PLYWOOD REALLY ALL IT TAKES

TO UNLOCK THE MYSTERY OF THE MIMA MOUNDS?

OR COULD THERE BE SOMETHING

EVEN MORE SURPRISING AT WORK HERE?

TO FIND OUT, I'M GOING TO HAVE TO DIG DEEPER, LITERALLY.

KILLED IT.

COULD THE MYSTERIOUS MIMA MOUNDS OF WASHINGTON STATE

HAVE BEEN SHAPED BY CENTURIES OF EARTHQUAKES?

I'M PUTTING THAT THEORY TO THE TEST

WITH A PIECE OF PLYWOOD,

SOME SAND AND A HAMMER TO REPLICATE SEISMIC ACTIVITY.

LOOK AT THAT!

ALL OF A SUDDEN, IT'S FORMING MOUNDS ON THE SURFACE.

RIGHT DOWN HERE, YOU CAN SEE

WHAT LOOKS EXACTLY LIKE MIMA MOUNDS

BUT ON A MUCH SMALLER SCALE.

THIS IS UNBELIEVABLE.

I ACTUALLY DID NOT KNOW IF THIS WAS GOING TO WORK.

PROBLEM IS, I'M NOT SURE IF THIS SCALES UP

TO A LARGER LEVEL

AND REALLY COULD BE SOMETHING THAT EARTHQUAKES FORM.

TO FIGURE THAT OUT, I NEED MORE INFORMATION ABOUT THE NATURE

OF THE SEISMIC ACTIVITY IN THE AREA.

SO I'M HEADING TO MEET DR. JOHN VIDALE,

THE DIRECTOR OF THE PACIFIC NORTHWEST SEISMIC NETWORK

AT THE UNIVERSITY OF WASHINGTON.

SO, IN THIS PARTICULAR AREA,

IN THE SEATTLE REGION,

THERE'S A LOT OF SEISMIC ACTIVITY, RIGHT?

YEAH, WE HAVE A LOT OF DIFFERENT KINDS OF EARTHQUAKES.

AND IT'S, UH, ONE OF THE PRIMARY DANGERS

OF NATURE AROUND HERE.

SO COULD BIG EARTHQUAKES LEAD TO BIG MOUNDS?

I TELL JOHN ABOUT MY FINDINGS USING THE BOARD,

HAMMER AND SAND.

I DON'T KNOW IF YOU CAN SCALE THAT UP, THOUGH.

YOU'RE THE SEISMIC EXPERT. I MEAN, WHAT--

WHAT ARE YOUR THOUGHTS? - PEOPLE DO THAT WITH DRUMS.

AND THEY PUT STEEL FILINGS.

AND IT MAKES ALL SORTS OF PRETTY PATTERNS IF YOU SHAKE IT.

BUT, UNFORTUNATELY, THE GROUND DOESN'T ACT THAT WAY.

IF YOU SHAKE IT, IT DOESN'T JUST SHIFT

AROUND INTO LITTLE PILES VERY EASILY.

IT JUST STAYS RIGHT WHERE IT WAS AND VIBRATES.

AND, IN YOUR EXPERIENCE, YOU'VE NEVER SEEN ANYTHING

LIKE THAT FROM SEISMIC ACTIVITY?

NOTHING LIKE THAT.

JOHN TELLS ME THAT EARTHQUAKES

CAN RESHAPE THE LAND IN VARIOUS WAYS.

THEY CAN CAUSE THE EARTH TO CRACK OPEN

OR TRIGGER TSUNAMIS AND LANDSLIDES.

BUT THERE'S NO DOCUMENTED INCIDENT OF SEISMIC ACTIVITY

CAUSING REPEATED, UNIFORM MOUNDS TO FORM ON EARTH'S SURFACE.

SO IT SOUNDS LIKE EARTHQUAKES

PROBABLY DIDN'T CREATE THE MIMA MOUNDS.

AND THEY DON'T SEEM TO BE MAN-MADE OR GILGAI EITHER.

I'M BUILDING AN IMPRESSIVE LIST

OF FACTORS THAT DO NOT EXPLAIN THESE MYSTERIOUS MOUNDS.

BUT I'M STILL SEARCHING FOR THE ONE THAT DOES.

EACH FAILED THEORY IS BRINGING ME CLOSER.

BUT I HAVEN'T GOTTEN ENOUGH INFORMATION ABOUT

THE INTERNAL STRUCTURE OF THE MOUNDS YET.

WHAT I REALLY NEED IS TO ACTUALLY SEE INSIDE ONE.

I'VE GOTTEN PERMISSION TO OPEN UP

A MOUND ON PRIVATE LAND,

ONE THAT I'VE BEEN TOLD DOES NOT CONTAIN

ANY SENSITIVE ARTIFACTS.

SO I'M BRINGING IN A BIG MACHINE.

THE ONLY WAY FOR ME TO GET DOWN IN THESE THINGS

AND GET A GOOD CROSS-SECTION IS TO USE A BIG TOY.

IT'S NOT EXACTLY CUTTING-EDGE TECH.

BUT, MAN, IS IT FUN!

KILLED IT.

WOO-HOO-HOO!

YEAH!

ALL RIGHT. LET'S SEE WHAT WE GOT.

I IMMEDIATELY NOTICE SOMETHING INTERESTING.

THE DISSECTED HILL IS MADE UP OF TWO DISTINCT LAYERS OF SOIL.

SO WHAT WE GOT IS WE GOT A NICE 2-1/2 FOOT SECTION

OF REALLY DARK DIRT INTERSPERSED

WITH THESE ROCKS, LITTLE TINY PEBBLES AND THINGS.

AND THEN THERE'S A REALLY GOOD LAYER

RIGHT HERE OF LIGHTER-COLORED STONE.

SEEMS A LOT HARDER DOWN HERE.

BUT I'M NO GEOLOGY EXPERT.

AND I'M NOT SURE HOW TO INTERPRET WHAT I'M SEEING.

SO I REACH OUT TO DR. JENNIFER BURNHAM,

A SOIL SCIENTIST.

SHE AGREES TO MEET ME AT THE MOUND.

SO, FROM HERE TO HERE,

YOU DON'T REALLY SEE A WHOLE LOT OF DIFFERENCE.

IT'S ALL FAIRLY CONSISTENT.

IT IS. IT'S VERY UNIFORM.

WE DO HAVE A VERY CLEAR BOUNDARY WHERE,

NOT ONLY DOES THE COLOR CHANGE

BUT, EVEN AT FIRST GLANCE,

YOU CAN SEE THE SIZE OF THE ROCKS VARIES.

WE TAKE A CLOSER LOOK AT THE TWO LAYERS

WITH THE AID OF A SIEVE.

FIRST, THE TOP LAYER...

SO, HERE, WE'D SAY THERE ARE FAR MORE PARTICLES

THAT ARE SMALL THAN THERE ARE LARGE.

THEN, THE BOTTOM.

TAKE IT AWAY.

ALL RIGHT.

BASICALLY, THE RATIO OF THE BOTTOM

IS, UH, REALLY SKEWED TOWARDS BIG ROCKS.

CORRECT.

JENNIFER SAYS THAT THIS DISTRIBUTION,

SMALLER-GRAIN SEDIMENT ON TOP

AND LARGER CHUNKS AT THE BOTTOM,

IS UNUSUAL IN A SEISMICALLY ACTIVE ZONE.

WELL, IN A EARTHQUAKE-PRONE AREA LIKE WE ARE HERE,

YOU MIGHT NOT EXPECT IT TO LOOK LIKE THAT.

YOU MIGHT EXPECT MAYBE SOME OF THE LARGER ROCKS

TO BE NEAR THE TOP.

THAT'S BECAUSE OF A PHENOMENON

CALLED GRANULAR CONVECTION,

ALSO KNOWN AS THE BRAZIL NUT EFFECT.

TAKE A JAR WITH RICE AND BRAZIL NUTS.

AND THEN YOU SIMULATE SEISMIC ACTIVITY BY SHAKING 'EM UP.

THE SMALLER RICE KERNELS FILTER

DOWN INTO THE SPACES CREATED BY EACH JOSTLE

AND PUSH THE LARGER NUTS UP.

SO, WITH ALL THE EARTHQUAKES THAT HAVE STIRRED UP

THE SOIL HERE OVER THE CENTURIES,

YOU WOULD EXPECT TO SEE LARGER STONES

IN THE TOPSOIL LAYER

WITH SMALLER PARTICLES BELOW.

BUT IT LOOKS LIKE EXACTLY THE OPPOSITE IS HAPPENING.

SO THE QUESTION IS, WHY?

WHAT SECRET IS THE SOIL REVEALING?

WHAT DO YOU THINK THAT THIS COULD BE?

SO I THINK THAT THE EVIDENCE FITS BEST

WITH WHAT'S CALLED THE GOPHER HYPOTHESIS.

LIKE, THE IDEA THAT GOPHERS BUILD THIS?

CORRECT.

I'VE OPENED UP

ONE OF WASHINGTON STATE'S FAMOUS MIMA MOUNDS.

AND WHAT I'VE FOUND IS BIZARRE

FOR AN AREA PRONE TO SEISMIC ACTIVITY,

A SOIL STRUCTURE WHERE THE BIG STONES ARE AT THE BASE,

CONTRADICTING THE PHENOMENON KNOWN AS THE BRAZIL NUT EFFECT,

WHICH HOLDS THAT SMALLER PARTICLES

ACTUALLY SETTLE AT THE BOTTOM OVER TIME.

I'VE ELIMINATED HUMANS AND EARTHQUAKES

AS THE MAKERS OF THESE MOUNDS.

BUT SOIL SCIENTIST JENNIFER BURNHAM

HAS A SURPRISING ALTERNATIVE THEORY.

WHAT DO YOU THINK THAT THIS COULD BE?

IT IS A BIT INCOMPREHENSIBLE

TO THINK ABOUT THAT SMALL POCKET GOPHERS

COULD HAVE CREATED THESE MOUNDS.

WAIT A MINUTE.

DOES JENNIFER REALLY THINK THAT CUTE LITTLE GOPHERS

BUILT THE HUGE MOUNDS AT MIMA?

POCKET GOPHERS ARE BURROWING RODENTS THAT AVERAGE

JUST 8 INCHES IN LENGTH.

THEY SPEND MOST OF THEIR LIVES UNDERGROUND,

IN A TUNNEL SYSTEM WHERE THEY NEST,

REST AND STORE FOOD.

GOPHERS ARE KNOWN TO HAVE INHABITED THE AREA

AROUND THE MIMA PRAIRIE AT ONE TIME,

ALTHOUGH THEY'VE LONG SINCE MOVED ON TO GREENER PASTURES.

OKAY, SO LET ME JUST GET THIS STRAIGHT.

THESE ARE HUGE MOUNDS.

I THINK IT-- I THINK, IF MOST PEOPLE WALKED UP

TO THIS AND THE IDEA

WAS PRESENTED THAT GOPHERS MADE IT,

THEY'D SAY, "NO WAY. THOSE ARE TOO BIG."

THEY'RE HUGE.

I MEAN, THEY'RE ALMOST 6 FEET TALL,

SOME OF 'EM OVER THAT. - YOU'RE RIGHT.

BUT IT'S NOT ONE GOPHER

DOING THESE IN A SHORT ORDER OF TIME.

IT'S, UH, MANY GENERATIONS OVER--

OVER HUNDREDS OF YEARS.

IT SOUNDS CRAZY.

BUT JENNIFER THINKS THE STONE LAYER AT THE BOTTOM

OF THE MOUND IS A SMOKING GUN.

WHAT'S KEY IS THE SIZE OF THE COBBLES

THAT WE'RE FINDING HERE.

A GOPHER CAN'T MOVE SOMETHING LIKE THIS

THROUGH THEIR BURROWS.

THEY CAN ONLY MOVE THE SMALLER PARTICLES THAT ARE HERE.

SO THEY'LL BURROW AROUND

AND UNDER THESE LARGER CLASTS AND,

EVENTUALLY, OVER TIME,

WILL START SINKING TO THE BOTTOM.

AND THAT'S EXACTLY WHAT WE'RE SEEING HERE.

BUT THERE'S ONE KEY WAY THE MIMA MOUNDS

ARE NOT LIKE TYPICAL BURROWS.

MOST OF THE TIME, GOPHERS DIG DOWN.

WHY WOULDN'T THEY BE DOING THAT HERE?

GOPHERS WILL NOT BUILD MOUNDS

UNLESS THEY CANNOT BURROW DOWNWARDS.

SO, IF THERE'S SOMETHING THAT'S HARD TO GET THROUGH,

THEN THEY WILL TEND, UM, TO DIG--

OR BUILD THEIR MOUNDS HERE.

AND WE KNOW FROM OUR E.R.T. TEST

THAT THERE'S HARDER MATERIAL

BENEATH THE ENTIRE MIMA MOUND PRAIRIE.

NOW I CAN ALSO SEE IT

RIGHT BELOW THE LAYER OF LARGER STONES.

AND I CAN'T IMAGINE A GOPHER BEING ABLE TO BURROW THROUGH IT.

AND JENNIFER TELLS ME THIS AREA USED TO HAVE A HIGH WATER TABLE,

WHICH IS ANOTHER IMPEDIMENT

THAT PREVENTS GOPHERS FROM BURROWING DOWN.

BUT, STILL, IS IT REALLY POSSIBLE

FOR SUCH TINY CRITTERS TO MOVE SO MUCH DIRT?

JENNIFER HAS ONE MORE PIECE OF TECH

TO HELP SUPPORT THE THEORY,

A NEW COMPUTER PROGRAM

THAT SIMULATES GOPHER BURROWING BEHAVIOR.

I'LL SHOW YOU THIS COMPUTER MODEL I HAVE HERE.

IT CAN CROSS-REFERENCE STANDARD GOPHER STATISTICS,

SUCH AS THE AMOUNT OF SOIL

A GOPHER CAN MOVE ANNUALLY AND THEIR TYPICAL HOME RANGE

WITH SITE-SPECIFIC CONDITIONS LIKE THE HARD SUBSTRATE

WE DISCOVERED UNDER THE MIMA MOUNDS

AND SHOW US WHAT WOULD HAPPEN

AS GOPHERS CONSTRUCT THEIR BURROWS.

OKAY. SO LET'S SEE THIS MODEL.

THE GROUND STARTS FLAT.

BUT, AS THE SIMULATION SPEEDS

THROUGH THE YEARS OF GOPHER ACTIVITY,

SMALL HILLS START TO FORM.

OH, WOW!

THE REDDER COLORS INDICATE THAT THE HEIGHT IS INCREASING.

THE WHITER... - OH, MY GOODNESS.

...WHITER COLORS ARE INDICATING, UM, LOWER ELEVATION.

SO THIS IS JUST A RANDOMIZED MODEL.

IT-- IT LOOKS--

IT LOOKS JUST LIKE THE AERIAL IMAGES WE TOOK.

THE MODEL IS SHOWING ME SOMETHING

THAT SEEMED SO UNLIKELY JUST MINUTES EARLIER.

OVER THE COURSE OF 500 TO 700 YEARS,

SUCCESSIVE GENERATIONS OF GOPHERS

COULD HAVE FORMED MOUNDS AS BIG AS THE ONES

THAT SURROUND US HERE AT THE MIMA SITE.

THAT IS FANTASTIC.

AND YOU COULD NEVER HAVE SEEN THIS WITHOUT

RUNNING A MODEL LIKE THIS,

RUNNING SOME HIGH-TECH SCIENCE.

YEAH. IT'S ONE IMPORTANT COMPONENT

OF THIS PIECE OF THE PUZZLE THAT WE'RE TRYING TO SOLVE.

WHEN I STARTED THIS INVESTIGATION,

I DEFINITELY DIDN'T SEE THIS COMING.

BUT TECHNOLOGY MAY FINALLY BE REVEALING

THE LIKELY ARCHITECTS OF THE MIMA MOUNDS.

NOT THE NATIVE INHABITANTS OF THE PACIFIC NORTHWEST,

SINCE WE FOUND NO ARCHAEOLOGICAL EVIDENCE

OF HUMAN HABITATION HERE.

NOT CLAY-RICH SOIL EXPANDING

AND SHRINKING WITH THE SEASONS,

SINCE OUR ELECTRICAL TESTING REVEALED NO CLAY CONTENT.

AND NOT SEISMIC ACTIVITY,

WHICH TENDS TO LEAVE BEHIND CREVICES,

NOT PIMPLES.

INSTEAD, THE MIMA MOUNDS APPEAR

TO BE THE WORK OF GENERATIONS OF GOPHERS BUSILY

MOVING THE SOIL UPWARD FROM BELOW

AND LEAVING BEHIND A LANDSCAPE LIKE NO OTHER.

THE MIMA MOUNDS HAVE PRESERVED THEIR SECRETS FOR MILLENNIA.

THEY JUST NEEDED SCIENCE TO DECODE THEM.