Creation of the Great Lakes | How the Earth Was Made (S1, E7) | Full Episode | History

earth a 4.5 billion year old planet still  evolving as continents shift and clash   volcanoes erupt glaciers grow  and recede the earth's crust   is carved in numerous and fascinating ways  leaving a trail of geological mysteries behind in this episode the great lakes of north  america the largest expanse of fresh water   on the planet are investigated they hold  20 percent of the world's fresh water   and provide drinking water  for nearly 10 of americans   these five lakes are among the world's greatest  natural wonders but their origins are a mystery   now geologists are investigating piecing  together the clues that lie hidden   in this extraordinary landscape delving  deep into a vast underground salt line   behind the torrential flow of niagara  falls climbing a mile high glacier where clues to understanding  the great lakes formation   also provides a window into the  formation of the earth itself the five great lakes superior   michigan huron and erie pour over one of the  world's great waterfalls niagara into lake ontario the mighty torrent of the  falls empties excess water from   four of the five great lakes out to the sea for geologists the lakes are a natural wonder  and a puzzle and scientists are on the trail   of how they were formed with rocks as their  clues and ice lava and water as their suspects their investigation begins at these seemingly  ordinary industrial buildings beside lake huron   hundreds of feet below ground  here there's a remarkable secret deep below lake huron and also lake michigan   are vast salt mines carved out  directly beneath freshwater lakes right now we're 750 feet below the  surface of the earth we're in the   largest underground salt mine in the world and  we're below lake euron large freshwater lake   amazingly this salt deposit  was uncovered by accident   they were joined for oil and they hit salt and  that was the end of looking for looking for oil   they just kept on digging for the salt this  salt deposit is the investigator's first clue evidence that there was once an ancient sea here many years ago the the salt was formed in a great  salt lake and the evaporation dry seasons the salt   dropped out evaporated out and formed  the salt that we're actually mining in there are hundreds of layers of salt  leading investigators to conclude   the sea must have dried up and refilled hundreds  of times scientists would later prove this sea   finally evaporated millions of years ago 35  of north america's salt comes from these mines   salt used to melt ice on frozen roads and  sidewalks salt used to season food the   remains of million-year-old seas all coming  from beneath lake huron and lake michigan the salt deposit is massive there's probably  trillions of tons of salt in the deposit   it extends all the way down to detroit all of  lake euron the salt is under it and of michigan the salt is soft and over millions of  years the salt layers should have worn away   why haven't they it's because the salt is  protected by a vast impenetrable layer of   rock that lies like a giant basin beneath  lakes michigan and huron and stretches under   lake erie like the porcelain lining a bathtub  the rocky basin holds the lake's fresh water geologist john zawiski and a team of divers are  hunting for clues to the rocky basin's origins   they're heading for thunder bay a  small island at the edge of lake huron   as he walked along the beach zawisky  discovered some crucial evidence   seemingly insignificant rocks  that were overlooked for decades   but zawiski suddenly realized what he was looking  at fossilized remains of ancient sea creatures   i was seeing something that many geologists  had never seen when they visit this island   there were the heads of giant lime secreting  sponges that were some of the main reef builders   zawiski uncovered a perfectly preserved fossil of   a giant sea sponge that must have  come from an ancient coral reef for the past five years zawiski's divers have  been surveying the lake to discover the size   of the ancient coral reef they believe it's  hundreds of feet thick and extends deep below   lake huron and zawiski has proof these  rocks are extremely old the time period   can be pretty confidently bracketed  at right around 385 million years ago america was then a very different  place 385 million years ago   its land mass lay in the southern hemisphere  a land covered by ancient warm coral seas   this region was just south of the equator  in tropical conditions and shallow seas had   swamped many of the land areas of the earth at  that time year in year out coral reefs decay   naturally and turn into a soft rock limestone and  much of the rocks of whiskey's divers find under   thunder bay island consists of layer upon layer  of this limestone from successive coral reefs   but millions of years ago some of this soft  limestone near the surface was changed when   the salty briny sea evaporated it  turned the limestone into a second   much harder rock something which would  decide the very shape of the great lakes this rock is limestone this other piece was  once the exact same material however it's   been converted by uh a process of brines creating  the conditions for recrystallization into a rock   that we call dole stone it's much harder than  limestone more weathering resistant and i can   easily demonstrate the difference between these  two calcium carbonate calcium magnesium carbonate   to show the relative hardness of the  two rocks zawiski uses an essential tool   in the geologist's arsenal let  me uh put a little acid on here   acid easily attacks and dissolves soft  rocks first how will the limestone react you can see a very violent reaction there carbon  dioxide gas is being released from the limestone   next the hard dolo stone let's go ahead and do  the acid test on it and you can see we don't   get this violent reaction almost no reaction  at all zawiski has proved the dolestone layer   is harder and more resistant than the limestone  the ancient ocean's salty water converted the   top layer of the limestone deposit into  a cap of hard resistant dole-stoned rock it's this that forms the super tough rock basin   under three of the five  lakes michigan huron and erie scientists were beginning to piece together  the chain of events that led to the formation   of the great lakes the clue's uncovered so far vast salt deposits provide evidence of an ancient  ocean the briny ocean changed soft fossilized   limestone into hard dollar stone dolestone makes  up the rocky basin under lakes michigan huron   and erie the tip of the rock basin the rim forms  steep cliffs that tower above these three lakes this immense wall of rock called the niagara  escarpment forms the boundaries of these   lakes and makes possible one of the world's  greatest natural spectacles niagara falls over this hard dolestone cliff three thousand  tons of water a second tumble from four of the   five lakes but it's more than just a miracle of  nature niagara falls is a vital clue that helps   scientists date when fresh water first began  flowing into what we now call the great lakes   the great lakes of north america geologists  have discovered three of the lakes were   formed in a vast rock-lined basin  laid down by an ancient lagoon   the question is when and they  think the answer lies here   niagara falls behind this curtain of water  lies the evidence to when the lakes were made like the overflow from a bathtub excess water  from four of the five lakes superior michigan   huron and erie spills over the falls into lake  ontario and all that water is changing the falls   change that can be measured and used to  calculate the age of the lakes themselves the falls were first studied by one  of modern geology's founding fathers   charles lyle lyle who'd pioneered the early  understanding of earth's secrets was intrigued by   the concept of geological time charles lyle came  to niagara region in the 1840s and he made very   important observations at niagara falls lyle was  using the principle that things that we see going   on today can be used as examples for what went on  in the past lyle believed the world wasn't shaped   in a few days or even years but by slow change  over millions and billions of years this directly   contradicted the much shorter time biblical  scholars said the world had been in existence   lyle realized that dramatic geological change was  going on in front of his eyes at niagara falls   if he could measure it he might be  able to calculate the fall's age   lion's technique was brilliantly simple he  noticed below the falls was a great gorge which   locals said was steadily increasing in length  as the water wore away the ledge of the falls   the falls they said were moving slowly upstream head to the base of the falls and you can  see why the cliff face is being worn away   the falls are formed by a cliff capped with  a ledge of the same hard dollar stone rock   created as we've seen by seawater beneath the  tough dolostone cap is a layer of much softer   rock called shale as the water crashes over the  gallis stone it erodes out these soft shales that   are underlying the dollar stone and the blocks can  fall down from the face on the right then you can   see these massive blocks of dollar stone that  have fallen down at the bottom of the waterfall each time the dollar stone ledge  collapses the falls move further upstream   lyle believed this process had been going on  for thousands of years and was still continuing   it had begun as the lakes were first formed when  water began wearing away the hard dollar stone   ledge of the falls to discover the age of the  falls all charles lyle needed was some simple math   he realized that the falls had started at the  niagara escarpment which is about 35 000 feet from   here so if the falls receded at one foot per year  and receded 35 000 feet that would give an age for   their present position of 35 000 years lyle's calculation was based on simple  measurements but wrong guesswork he thought   the falls were receding by one foot a year  but today we have much better records to go on this plaque commemorates table rock  which is where the falls were in   the beginning of the 19th century since that  time they've receded about 600 feet to my right so in the last 200 years the falls have  steadily retreated at a rate of not   one foot but an astonishing three feet a year   so instead of lyle's calculation of 35 000 years  old the niagara falls were a third of that figure   just 12 000 years old a mere blink of an  eye in earth's 4.5 billion year history in the search to find what created the great  lakes scientists now had a crucial clue   the age of one of their key features at  the same time the falls is the overflow   for all the upper lakes into lake ontario and  the sea so if the falls have only been around   for 12 000 years then it means the lakes  themselves must also be incredibly young now that scientists had worked out when the  lakes were created the next question was how   what immense force could have created not  one but five huge lakes a force so powerful   it must have left a trail of incriminating  evidence across the region geologist john   menzies scans the landscape to track the  mysterious force that created the great lakes and he spotted something unusual strange teardrop  shaped hills one after another called drumlins   some are small fat and streamlined  some are extremely elongated   this one is about almost a mile in length  150 feet high and about 200 feet across   this is the evidence that john  menzies has been looking for   there are many drumlin fields in north america  but this one is a particularly large field has   anywhere between 60 and 80 000 so it  is truly an enormous strumming field each drumlin points in the same direction  north to where an immense force came from   this tells menzies they were all created  by the same powerful object but what was it   the answer lies 4 000 miles  away high in the swiss alps here the culprit is plain to see snow  and ice switzerland is home to some of   europe's largest glaciers giant rivers  of ice that flow down mountain valleys glaciologist dr andreas bowder studies  how glaciers can transform the landscape   what he discovers here could also  point to how the great lakes were made   we measured the movement of the ice   this reflector reflects the laser signal coming  from a theodolite giving us the position of this   stake and then we can calculate the movement my  colleagues down here are drilling deep holes down   to the base of the glacier to install instruments  to understand how the glacier is changing here powder's measurements reveal this  glacier moves over 10 feet every month here a seemingly stationary glacier is shown   moving down the mountain recorded by  time-lapse photography over a year to find out what's driving it  powder climbs high up the glacier this glacier is thousands of years old  and almost a mile thick in some places   ice that's a mile thick weighs a  colossal 3.8 billion tons per square mile   that's the weight of 59 000 fully laden super  tankers and it's this immense weight that   makes the glacier such a force to be reckoned  with its weight is slowly pushing the glacier   down the valley gathering anything in  its path collecting rocks and debris the rocks act like the blades of a giant bulldozer   scouring the ground digging up  yet more and more rock and soil but when the temperatures rise the glacier melts   retreating up the valley and leaving rocks  and debris behind in huge piles this is how   the teardrop shaped drumlins back in north  america were formed they were bulldozed   landscaped by a powerful glacier a glacier  that may also have gouged out the great lakes the evidence is coming together   niagara falls dated just 12 000 years old this  suggests the lakes themselves are very young   the presence of thousands of drumlins pointing  to ice that carved out the great lakes it's a convincing case but there's one  problem the great lakes cover an area five   times the size of switzerland no glacier  that size has ever been known to exist   geologists were on the hunt for something even  more powerful that could have created such huge   destruction a kind of prehistoric  monster roaming over north america geologists are scouring the landscape searching  for evidence of a massive force one that was   capable of gouging out 12 trillion tons of  solid rock enough to create the great lakes of   north america it would be a body of ice so large  that it would break every record defy all logic   geologist john menzies hunts for evidence of this  prehistoric monster just south of niagara falls   this whole area was covered  by the ice with a tremendous   torrent of sediment and water between the  ice and this bedrock and as the sediment   moved across which produced these superb  striations and parallel scratches and marks and there's another clue giant boulders  of hard crystalline rock called granite these hard massive rocks sit in a flat  sandy landscape they shouldn't be here   this is what we refer to as an erratic  bowler it's granite it weighs some 80   to 100 tons it would actually be frozen up  into the base of the ice and then moved kind   of like a conveyor belt along on the base of  the ice down to this part of southern ontario   some four or five hundred miles to  the south from the canadian shield   where with ice retreat and the eventual melting  of the ice this boulder's been left to sit   as we see it today erratic boulders moved hundreds  of miles from northern canada scratches on the   bedrock and drumlin hills the evidence is  mounting there was ice here once lots of ice   geologists map these glacial features  together and an extraordinary picture emerges   not of a glacier but of a vast ice sheet  one mile thick and over 2 000 miles long   it stretched all the way from the north  pole as far south as chicago and new york   leaving a trail of destruction in its  path here was a force powerful enough   to create the great lakes but even this  vast sheet of ice couldn't have gouged   out basins that are over 1300 feet deep  it seemed the culprit wasn't working alone   at scarborough bluffs just 100 feet from  lake ontario john menzies has spotted an   unusual deposit at the cliff face layers of rock  provide him with a kind of geological time machine   the deeper he looks the further back in time he  goes you could say that this is a journey through   the last 60 000 years of geological history  in this part of canada this lower formation   is 65 000 to about 40 000 years ago the next  layer is between 25 000 and 10 000 years ago   menzies focuses on the dark layers  sandwiched between the light ones   what we have here is a sequence of sediments  which illustrate the movements of the ice front   back and forward across this part of canada  these dark layers mark the exact end of each   ice age formed of organic material when plants  grew again at warmer temperatures here john   menzies has proof that ice ages return twice  to this spot during their cycles of destruction in fact across the great lakes region geologists  have found evidence of up to 10 separate enormous   ice sheets as each new ice sheet advanced it  carved the great lake basins deeper and wider   eventually forming the largest lake system in  the world but the ice left vast areas unscathed   it suggests there was some other force at play  something in the lake's ancient past that set them   apart from the surrounding landscape making them  particularly vulnerable to the ice sheets attack menzies decided to dig deeper down to the  landscape that existed before the ice ages   going back 2.5 million years he found  evidence of a chain of ancient rivers flowing   across what's now the great lakes region the  pre-glacial topography of the great lakes basin   mirrors the existing great lakes system  and great lakes basins that we see today   the ancient river's pattern and flow exactly  mirrored the shape and position of today's lakes   it's no coincidence these rivers formed valleys  that affected the way the ice sheets moved   as the lay sheet advanced to the south it would  tend to follow the three glacial rivers and so   you get these really fast moving zones of ice  which create a tremendous amount of erosion   in these pre-existing depressions the ancient  river valleys funneled the ice sheets into   fast-moving super ice floes menzies believes  the coarse sediments the rivers left behind   dramatically accelerated the ice sheets flow this  sediment acts as a kind of lubricant a bit like   ball bearings underneath the ice would  actually speed it up quite quite appreciably   these fast streams of super ice were even more  destructive to the landscape the case is coming   together drumlins clustered across the landscape  testify to the vast ice sheets brutal power dark layers of rock reveal  the ice was a serial attacker   while a network of ancient rivers  left some areas more vulnerable to   these attacks turning slow lumbering ice  into destructive fast-moving super ice these gouged out all the loose rock and  sediment down to the hard dollar stone layer   the rocky lake floor the result the basins of  the great lakes case closed for three of the   five lakes inside the rocky basin but not for the  other two lakes ontario and superior are outsiders   the theory doesn't fit they're simply too deep  in an attempt to find out why a daring underwater   expedition would investigate lake superior  the largest deepest greatest lake of all the hunt is on to discover what formed  the great lakes of north america   geologists have found compelling evidence  that the central lakes lie in a vast   rock-lined basin laid down by an ancient  lagoon gouged out by giant ice sheets when it   comes to lake superior the theory doesn't fit the  greatest of all the lakes at over 1300 feet deep   it could almost submerge the empire state  building and it lies outside the rocky basin   lake superior isn't just deeper than the other  lakes its floor is the lowest place on the north   american continent over half of this mighty  lake lies below sea level the question is why canadian geologist henry halls was convinced the  explanation could be found at the very bottom   of the lake the opportunity came up to study a  very remote part of the lake it's almost in the   geometrical center and it's called superior  shoal and people didn't know what the rocks   were there and they didn't know why it was  there in the summer of 1987 halls led an   expedition to the lake's dark unexplored  depths we went down it took us about 15   minutes to go down and it gets completely black  apart from the searchlights of the submersible   and when we reach the bottom the the pilot he  said this is very strange he said i'm getting uh   echo sounds coming back he said more or less from  all directions it does look almost vertical it is   where to go it's more than a vertical more than  vertigo we've heard in fact it's hanging over us deep in the center of the lake on  the border between canada and america   halls came across a strange rock formation the  pilot said it seems that we're in some sort of a   chimney or something like this  he said i'm not sure what it is halls and his submersible were in a  deep canyon 1200 feet below the surface   intrigued he took an even  closer look at the canyon walls and as we climbed i started to see striations  like this they were actual glacial striae   on the sides of what presumably was a canyon  we are continuing to move up this vertical face   uh halls had uncovered a vast canyon lined with  striations or scratches from the glacier that had   carved out the lake but it was the type of rock  that was the clue to lake superior's exceptional   depth he used the subs robotic arms to take rock  samples from the canyon walls the canyon was made   of dark basalt rocks the discovery of this rock  took the investigation in a surprising direction basalt could only have been formed  by intense volcanic activity basalt is created when hot magma deep  within the earth wells up to the surface a billion years ago immense forces pulled the  earth's crust apart here forming a rift valley   hot magma seeped up through  the cracks in the thin crust   as it cooled it lined the valley  with a layer of hard basil   then over millions of years the rift was filled  with soft sedimentary rocks it was a tremendous   thickness of infill in that lake lying above those  volcanic rocks and all of this is relatively soft many geologists believe the exact same volcanic  action accounts for the formation of the fifth   and final lake ontario on average is the  second deepest lake a separate rift valley   appeared here much later than the one under lake  superior the volcanic split in the landscape   stretched as far as the ocean creating  lake ontario and the saint lawrence seaway millions of years later the mile-high  ice sheet easily carved out the weakened   rift valley structures under  lake superior and lake ontario   the extraordinary story of how the great  lakes were made is almost complete ice   sheets repeatedly carved out soft rock down  to the hard basins of the central lakes and to the north ice attacked  billion-year-old rift valleys   to make the deepest lake lake superior the  same action was repeated at lake ontario   when the ice melted for the last time 14 000  years ago it filled the lakes with fresh water   it sounds straightforward but there's a problem  there's so much ice the great lakes should be   many times bigger than they are today just  when geologists thought they'd solve the   mystery of how the lakes were formed a new  puzzle emerges where did all the water go   geologist john menzies is investigating exactly  what happened at the end of the last ice age   when a vast ice sheet one mile thick and  stretching to the north pole started to melt he believes it was so large it should have created  far bigger lakes than the ones we see today   he's looking for evidence of  one of these prehistoric lakes   as the ice sheet melted a vast freshwater  lake appeared that geologists call   iroquois then later as lake iroquois dried up  it left beaches which can still be seen today menzies believes he can  detect these ancient beaches   in the gently sloping landscape  surrounding lake ontario as menzies drives up hill away from the present  day lake he's traveling back in time across   lake iroquois ancient shores we're crossing one  shoreline after another the reason we know their   shorelines is that they contain large zones  of sand beach sands and beach bars and spits   the oldest big about twelve thousand years ago  the bottom shoreline being about 6 000 years ago getting to the top of the hill 400 feet  above the level of today's lake ontario   menzies is standing on the ancient shore of the  original lake the present-day lake ontario is   off there in the mist and we're sitting about 400  feet plus on this beach which is was formed maybe   10 000 11 000 years ago and then the ultimate  oldest beach is about 12 000 years ago   these ancient beaches now buried  under the surrounding landscape   are evidence of a colossal freshwater lake we're  looking at a vast amount of water when you think   of the water it stretched from here to beyond  the present lake way into new york state beyond   into rochester so it's a huge enormous inland  sea despite their size the great lakes today   are just a small fraction of these vast  prehistoric lakes the water has vanished geologists want to know how they emptied 50 miles east of toronto at india river  canyon menzies picks up the trail of the   missing water torrents okay what we have  here is an enormous sub-glacial pothole   formed by subglacial melt water exiting underneath  the ice sheet typically formed with a large roller   ball which rolls around in these really torrential  vortices the malware is chock full of boulders and   sediments and in this instance it's  drilled itself the whole way through these potholes are evidence of a catastrophic  flood of huge volumes of water moving at high   speed this flood needed an escape route  and menzies believes he's found the place   this would be an enormous turn possibly at least  a couple of miles across and could easily have   been two three four hundred feet deep moving at  an incredible velocity nearby a steep gorge yet   more evidence of the floodwaters terrifying power  the stream that remains today couldn't have cut   such a huge amount of rock and what we've got  left is what we call a misfit stream which is   the fairly small indian river and this if you like  is the remnant of that enormous torrential flood   geologists believe as the ice sheet retreated it  uncovered this ancient india river outlet allowing   vast amounts of melt water to tear down towards  the sea finally 12 000 years ago the ice retreated   freeing the saint lawrence seaway and allowing  the lakes to settle into their present flow the story of the great lakes is coming together  ice sheets repeatedly ground out deep basins   digging out ancient weaknesses in the earth's  crust prehistoric beaches show that when the   final ice sheet melted the water flooded the  basin to create vast super lakes like iroquois   and as the ice finally retreated 12 000  years ago the excess water drained away   to leave the great lakes we know today but even  now as we know how the great lakes were formed   they are still changing and scientists predict  one day the lakes might disappear forever the great lakes evolved over a billion years   today they're a vital link between the cities  bordering the lakes and the sea they provide   over 20 million people with drinking water  and irrigate crops throughout the midwest   but in the past few years fears have  grown about the great lakes future   water levels are falling people who  have worked the lakes for years believe   they can already see a change we noticed a drastic  decrease in water levels right after the september   long weekend where the water in a week dropped  a foot and throughout the remaining of the fall   it went down about another two feet and  you can notice that by the pinker or the   brighter colored rock versus the rock  that's typically exposed to the weather   and what we saw there was a clear example of how  the water has dropped um a good three to four feet many have been quick to blame global  warming for the fall and lake levels   but geologists believe there is another force  at work the ice sheet that cut out the lakes was   so heavy it pushed down on the earth's crust now  the ice sheet has gone the crust is bouncing back incredibly nine thousand years since the end  of the last ice age the ground is still lifting   in the north where the ice  was thickest land has risen   by as much as eighteen hundred  feet since the ice melted away toronto's famous cn tower appears to be getting  higher as the crust bounces back the land it's   built on beside lake ontario rises nearly an inch  each year the cn tower is part of the landmass   here so in fact it's rising out of the land in  fact the whole land surface is rising slowly lake nipissing today is a small body  of water to the north of lake huron   twelve thousand years ago when the ice began  to melt and lake nipissing first formed   it lay at sea level lake nipissing an enormous  lake there again as the land rebound so the lake   eventually drained out and the land rose slowly  so the land is now 400 450 feet above sea level   geologists call this crustal rebound and it  dramatically affects the delicate balance   of the network of small rivers that feed the  lakes this is an interesting example if we if we   think of trying to trying to explain crystal  rebound and we look at this river as it flows   out into the lake at the moment if we have  crossed a rebound the land comes back up   this river in fact will cease  flowing out into this lake it's this crustal rebound that's partly  responsible for the fallen level of the lakes   and as the lakes empty their weight decreases  allowing the crust to bounce up even faster   lake levels will fall so the amount of  water in the basin will in fact become less   and the effect of that will increase the rate of   crustal rebound land will come up even faster  than it's already doing and continues to do as the crust rises the lake slowly empty  but in a few thousand years the lakes will   face another even more dramatic change one  of the exciting things about geology these   days is not only looking at the past but  it's looking into the future in other words   having the ability to start to predict what  might happen in the next several millennia and the future is here at niagara falls at least  in geological terms every year the falls are   retreating three feet upriver only 12 miles and 21  000 years to go before they're back into lake erie   when that happens everything will change and  fast if the falls eroded all the way back to   lake erie which would take some thousands of  years the levels of all the upper great lakes   here on superior michigan would adjust to the  lowered level of lake erie by dropping as well the land between the falls  and the lakes acts as a block   it's the niagara escarpment  topped with hard dollar stone rock when the falls cuts its way  through this rock the water   levels in all the lakes to the west  would drop by a staggering 180 feet   the height of niagara falls almost  all of lake erie would drain away one day the lakes may disappear altogether   but geologists also predict a new  cycle of ice ages will begin again so an ice age would begin and the size age would  then cover we would expect at least 30 percent   of the land surface as it did in the previous ice  ages and when the ice returns the lake basins will   be cut even deeper before filling again with water  the largest freshwater lake system in the world   has had an extraordinary past a basalt lined  canyon discovered at the bottom of lake superior   shows that two great rifts opened up below lakes  superior and ontario fossilized sea sponges are   evidence of an ancient briny sea that laid  down the rocky bowl that holds lakes michigan   erie and huron thousands of drumlin hills are  proof that vast ice sheets repeatedly scoured   out the lake basins born just 12 000 years  ago the great lakes as we know them today   are just a transient feature they've only existed  for the geological blink of an eye but their story   hasn't ended yet the great lakes are changing and  evolving an endless process like the earth itself you

Channel: HISTORY

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Keywords: history, history channel, history shows, history channel shows, how the earth was made, history how the earth was made, how the earth was made show, how the earth was made full episodes, how the earth was made clips, full episodes, How the Earth Was Made season 1 episode 7, How the Earth Was Made se1 ep7, How the Earth Was Made s1 e7, How the Earth Was Made s01, How the Earth Was Made 1X7, episode 7, Formation of the Great Lakes, Great Lakes, Great Lakes of North America

Id: wztD2yxuyhI

Length: 45min 12sec (2712 seconds)

Published: Sat Jan 23 2021

Reddit Comments

[u/rlauzon]

"Rise and fall of the Great Lakes" was better.

[u/iSmokeMoreThanCheech]

..........

So that tall tale of Paul Bunyan and his giant blue ox Babe was full of shit?!

Next you'll tell me that C19 isn't as deadly as we've been told.

[u/j0217995]

And God said "Let there be the Great Lakes" And it was freakin.awesome

And God said "Let the Great Lakes form the shape of a mitten out of the land so it looks like someone is giving me a high five..." And it was freakin awesomer

And God said "Let those Great Lakes make another body of land almost look like a mitten, so everyone can laugh at them when they also claim to the Mitten State...". And it was Wisconsin

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