I'm not in a position to provide you with a comprehensive answer to your actual question; however, I thought that some more context for the show might be valuable.

The "star" of the documentary is Graham Hancock who has been writing about an 'alternative' history of human civilization since the 90s. Most notably, his book "Fingerprints of the Gods" put forward the hypothesis that there was a civilization on earth that predated our own recorded history by about 10,000 years. The primary source of evidence for the time-frame came from a theory put forward by another author Robert Bauval in a book called the "Orion Mystery" that posited the pyramids of Giza were built to mimic the position of the stars in Orion's belt. There is a complicated argument involving Ancient Egyptian religion, the shafts in the Great Pyramid and the precession of the stars over millennia that leads to the conclusion that the design of the Egyptian monuments were intended to mark a specific period of time, approximately 13,000 years ago.

Taken at face value, it makes for a compelling story, but even Bauval himself admitted in a later book, that he had to fudge some things to make it all work out (while still clinging to the theory).

Hancock's book has a laundry list of other pieces of 'evidence' that amount to unrelated 'mysteries' or oddities from around the world often drawn from other works. Notably, those other works are exclusively popular publications not scientific ones.

Hancock eventually settles on the 'Atlantis' myth as being the pre-existing civilization; however, while the common understanding of Atlantis is an island that was in the Mediterranean, he draws his theory of Atlantis from a theory put forward by Rand and Rose Flem-ath in a 1995 book called "When the Sky Fell: In Search of Atlantis". The Flem-ath's believed that the historical Atlantis was not an island in the Mediterranean but rather the continent of Antarctica, in part based on the work of Charles Hapgood, a keen Atlantis researcher. There was evidence at the time from core-samples that Antarctica used to have a temperate climate (which has been since well established: cf. this article for example) and that supported Charles Hapgood's Theory of Earth Crust Displacement published in his 1958 book "The Earth's Shifting Crust" (which included a supporting forward by Albert Einstein) and which he and the Flem-Ath's accounted for Antarctica/Atlantis's shift to the pole as well as the myth of its disappearance.

The time period in which Hapgood believed Antarctica still had a temperate climate roughly coincides with the time frame that Bauval and Hancock pinned the the existence of their antediluvian civilization; that however, has been disproven (for example: Ingolfsson, O. (2004) Quaternary glacial and climate history of Antarctica.)

All of these authors, Hapgood, the Flem-Aths, Bauval and Hancock have assembled a compelling story that certainly captures the imagination—allusions to their theories show up in popular culture, for example in the 'Stargate' franchise. And although, superficially it appears that they have scientific evidence to support their claims much of that evidence doesn't hold up to scrutiny or more often, is only used to insinuate a conclusion rather than support it. Their work certainly does not constitute anything like scientific rigor and it shouldn't be considered anything more generous than a fun thought experiment. You do not need to dig very deeply before you find their connections to and inspiration from the likes of occult writer Colin Wilson and out-right fraudster Erich von Däniken who have made outlandish claims concerning ancient civilizations.

Hancock, in particular, as one of the most well-known of proponents of this grand theory of the existence of a prehistorical civilization, has a very poor reputation amongst scientists and historians. He's also notable for his laughable (and disproven) claims about the 'face on Mars' and its supposed connection to the Sphinx.

Having not yet watched the series, I cannot directly comment on any details presented; if there are any specific things you have questions about, please do ask! Folks who have watched it say it's more or less (and somteimes word for word) an adaptation of two of Hancock's books, which I have read most of. Others have already pointed out how ridiculously unoriginal Hancock is, and the wonderful irony of him talking crap about archaeologists constantly because Gobleki Tepe doesn't fir their theories when the site was excavated by... mainstream archaeologists. I will add to this with an edited version of an older post on Hancock, that links to even more posts on Hancock.

There's a handful of fundamental scientific concepts that I teach at the start of any archaeology or biological anthropology classes.

The first is how to make a convincing scientific conclusion. SupposeI told you there was a teapot circling the sun somewhere between Earth's and Mars's orbits. It's too small to be seen by a telescope, and no records exist of anyone putting it there. Should I expect you to believe me? Are you a fool for not believing me? Of course not. Philosopher Bertrand Russell first used this analogy to support his own atheism, but it applies to any scientific statement. The burden of proof lies on the claimant, and you can't expect people to buy a hypothesis that states its own unverifiability.

The second is the importance of context: no data point is significant on its own. It says nothing about the effectiveness of a drug if everyone who takes it has reduced flu symptoms in 48 hours if everyone else with the flu has reduced symptoms over the same time. Likewise, no single artifact can tell us much about anything. Where was it found? What was it next to? Are there lots of similar things? How similar is it to those things? Scientific conclusions must be made in the context of an entire data set.

Graham Hancock's writings disregard these concepts entirely. This is why people use the word "psuedoscience." It's not because any of his claims are bonkers- "bonkers" is relative after all- it's because he doesn't actually do any science but attempts to make scientific sounding claims.

Hancock's first books (e.g. Fingerprints of the Gods) trick readers by violating that second point. I've offered an in-depth critique of his chapter on Tiwanaku here, which outlines the evasive, sneaky rhetorical techniques Hancock uses to convince readers. (And the lies. So many lies.) The basic formula is:

• Hancock describes something cool in vague, romanticized terms. This is often done in the first person in a journalistic style to provide an air of legitimacy without needing to be thorough

• Hancock asserts the thing's mysterious nature. He does this actively by showing how things archaeologists said 100 years ago (or never said at all!) fail to explain the thing, or passively by ignoring decades of research, positioning himself as the first person to ask these questions.

• Hancock offers an additional, enticing observation that, having had all other context stripped away, functions as the single knowable fact

• Hancock suggests his kooky hyper-diffusionist explanation for that observation that only makes sense if the handful of observations he's provided are the only ones you know

Because Hancock has stripped away all context for his observations, he can make whatever claims he wants. And because most readers have no familiarity with archaeological literature outside their high school history books, they don't know how much information Hancock is not telling them. Archaeological claims are like puzzles: they are built of hundreds of little interlocking bits that might not include every detail when but still point to a cohesive picture when taken together. Hancock is the dude in the corner yelling that the whole puzzle must be wrong because the two pieces he pulled out of the box don't fit together. Maybe if he looked at the big picture he might find a place to put them, but he doesn't want that; he just wants your attention.

More recently, Hancock has shifted to theories that violate that first scientific fundamental. His book America Before is the culmination of his obsession with the Younger Dryas Impact Theory. He also popularized the theory on Joe Rogan's show, which I address here. The YDI was a supposed comet impact that caused drastic climactic changes and general environmental destruction at the end of the last Ice Age. Hancock had said for years that all his theories needed was a mechanism to destroy his ancient mega-civilizations. His first books claim that seismic activity buried a civilization under Antarctica. But once some evidence for the YDI as a cause for the Younger Dryas fluctuations was published, he quickly latched onto the idea, and suddenly this ancient progenitor civilization was in North America, buried under a comet. America Before spends most of its time on how this event would have wiped clean ancient advanced civilizations in the Americas.

But here's the thing. We've known since the start of the 20th-century that there was some wacky climate stuff going on at the end of the Ice Age. We've also known that there was significant environmental disruption, including widespread forest fires and sea level change. The YDI is a theory to explain those observations. Why did Hancock not pick up on it before? In all likelihood, because a meteor impact sounds a lot more likely to have destroyed as much as Hancock needed to be destroyed than "climate fluctuations."

All Hancock's talk of ancient advanced civs whose evidence was destroyed by a meteor is classic Russell's teapot. He wants you to believe there was something there, but has embedded in his hypothesis a mechanism by which the evidence for that thing was destroyed.

Yet, this is another level beyond a teapot. A global civilization of the type Hancock speaks would have left enormous amounts of evidence. At the very least: mines and quarries, expanses of agriculture, tools and tools and tools, genetic evidence in domesticated species, and cities. This isn't just a teapot in space, it's a teapot that's blasting radio signals. Hancock must believe this entire civilization existed exclusively along the now-submerged coasts where the archaeological record is inaccessible or irreparably distorted.

I go on a much longer rant about the logic at play here. To summarize that comment, Hancock loves to make a big deal out of disproving statements that were made with a fraction of the data we have now by asserting them as inherently true despite them being the result of inductive reasoning. "People building monumental architecture used ceramics" is, for instance, a claim arrived at in the early days of archaeology with a narrow survey of sites informed primarily by Eurocentric theory. It is not simply a common sense claim, and is as viable for critique as any other. Hancock would have you believe this "obviously true" statement is so enshrined in the way human societies work that any evidence against it as a radical revision of mainstream thought.

One can debate endlessly over whether Hancock's claims are provocative, ludicrous, nonsense, fun, dangerous, racist, novel, radical, dull, or any other number of adjectives. But that, I believe, is missing the point. If you're talking about the claims, Hancock has already won the best prize you could concede: a place on the stage of reasonable debate. His claims come from such a pathetic imitation of the scientific process that to evaluate them as statements of truth is pointless.

The more you look at Hancock's works, the more you see a guy doing their darnedest not really to argue that there was an Ancient Apocalypse, but to convince you that everything is mysterious, that archaeologists have never really done much research ever. He rarely discusses, rarely elaborates, rarely builds an argument; he jumps from "there's an unexcavated building at this site" to "archaeologists are entirely wrong about the site" without so much as a "because." His writing style is all about dropping a detail here and another there, moving on before you have time to question anything. The chapters in his book don't end with summaries, but with: "I don’t know what to make of these similarities" (that's an actual quote, he literally says that in Magicians). There is simply no attempt to use multiple lines of evidence, no attempt to point you to further reading outside things he himself wrote. Looking at the notes for the chapter on South America in Magicians, we see lots of self-citations, lots of travel blogs and news articles, lots of books he wrote the intro for, and lots of general audience texts from before 1960. He only cites the archaeologists he apparently has so much beef with in regards to a single throwaway line about the Amazon.

This is particularly egregious if you watch his Joe Rogan appearances. Note just how much time he spends actually making falsifiable claims versus how much time he spends whining about establishment orthodoxy. And while you're at it, note how many times he calls out any specific archaeologists. He really doesn't, and one can only imagine it's because he either doesn't know them or he doesn't want you looking it up to find out how much information is actually out there. He keeps his enemies vague and ill-defined so you can't argue against him. If he can get you to buy into this all, it doesn't really matter what outrageous claim follows.

If you're curious about evidence for or against the existence of Atlantis, this thread written by /u/kiwihellenist might be of interest

I’m a geologist and I have just finished the first episode on the site in Indonesia. My main issue is with his methods for assuming the date of the site, it goes against 2 very simple geological concepts - the law of horizontal deposition and the law of cross cutting relationships. Essentially they aren’t really dating the workings under the hill - they’re dating the sedimentary layers in which the workings are found. So the sediment could’ve been deposited 11.6kya but humans have dug through this layer to develop the structure at a later date. Because humans have dug through the ice age layer that’s c.11.6kya this really means the site is YOUNGER than this date (law of cross cutting relationships). This really is why dating the layers instead of the structure in this case is very misleading. The site itself seems very difficult to date after some browsing through articles. I’m not trying to be one of Hancock’s “sceptical scientists” but really the methodology for dating is all wrong and wouldn’t stand in any academic journal for any site. So instead of it being “see the academics won’t accept these dates because they’re too old!!” it’s more a case of academics won’t accept the dates because the methodology is wrong. Science is all about uncovering new data to work out complicated truths, I think Hancock being extremely sceptical without actually having undertaken a science degree is dangerous.

It's too late for this response to reach many eyes now, but it's worth getting an understanding of the history of the idea of submerged ancient civilisations. The idea developed in the 18th-19th centuries, entwined in an intimate relationship with white supremacist theories about supposed ancient migrations.

The central idea was that modern Nordic peoples were imagined to be the direct descendents of Hyperboreans, whose country sank beneath the North Sea; they were in turn descended from Atlanteans. The rest of humanity, meanwhile, are subhuman: a separate species. In the historical era, the descendents of the Atlanteans supposedly include people like the ancient Greeks (imagined to be a separate species from modern Greeks) and modern Germans; though also some ethnic groups that might at first sight seem more surprising, like Berbers.

Here's a snippet from Edward Bulwer-Lytton's 1842 novel Zanoni:

For the pure Greeks, the Hellenes, whose origin has bewildered your dreaming scholars, were of the same great family as the Norman tribe, born to be the lords of the universe, and in no land on earth to become the hewers of wood. Even the dim traditions of the learned, which bring the sons of Hellas from the vast and undetermined territories of northern Thrace, to be the victors of the pastoral Pelasgi, and the founders of the line of demi-gods; -- which assign to a population bronzed beneath the suns of the west, the blue-eyed Minerva and the yellow-haired Achilles (physical characteristics of the north); ...

Bulwer-Lytton focuses on the imaginary migrations: he doesn't delve back into the Hyperborean-Atlantean past. At the time there were serious books making serious claims about imaginary migrations, and books about an imaginary Atlantis, but synthesising the two had to wait for people like Helena Blavatsky and the Thule Society.

Here's an older post of mine that discusses the history of the idea, in relation to the notion that Santorini is Atlantis. Here's the relevant passage:

The believed location of Atlantis didn't just jump from the Atlantic Ocean to Santoríni. It had to do quite a lot of migrating, and most of that migrating was motivated by racism and nationalism. There's an amazing article by Dan Edelstein, 'Hyperborean Atlantis, Jean-Sylvain Bailly, Madame Blavatsky, and the Nazi myth' [Sci-hub link], where Edelstein shows that in the 18th century Bailly used the spurious equivalence 'Atlantis = Hyperborea' to turn Atlantis into a floating signifier: Atlantis could be anywhere, Atlanteans could be anyone.

The payoff for this for Bailly was that any admired group in history could be reimagined as descendents of Atlanteans. There was no need any more to imagine that everyone was descended from Noah (which would mean everyone is Semitic) or from ancient Indians (as per Voltaire). If Hyperboreans in the far north could be Atlanteans, that meant Nordic peoples could be imagined as descended from them: white Europeans could be Atlanteans. And the ancient Hellenes could be Atlanteans too.

Atlantis turned into a way of casting 'Nordic' Europeans as the archetype of all civilisation and culture, and casting evryone else as a separate, inferior species. But these ideas appealed to ethnic nationalists outside 'Nordic' Europe too, such as Marinátos.

The idea reached peak popularity among some leading Nazis in the 1920s-40s. Though it wasn't universally accepted by them: Himmler preferred to valorise ancient native Germans as the ancestors of the master race. The migration theory was better received by figures like Hans Günther, Herman Wirth, Alfred Rosenberg, and of course Hitler.

Here's a longer piece I wrote offsite earlier this year that goes into the history in a bit more detail, specifically in connection with 18th-20th century racist theories about Greek migration legends and how they tied in with supposed Atlantean migrations.

In addition to all of the quality answers already posted here, you might be interested in my comment on How did Old and New World Civilizations develop in roughly the same time scale despite being completely separated? It tackles part of Hancock's poppycock, which is the question of why populous, settled, agriculture-based societies did not arise prior to the Holocene.

One thing Graham brings up, even if we concede earlier humans had more tools/building knowledge than we used to think ergo no missing civilizations. Shouldn’t there be evidence of progression of those building skills and tools? Such as the temples on Malta?

Hancock is creative that’s for sure. But it does seem like he touches on some things where if an actual reputable archeologist brought up, would be taken a lot more seriously.

A lot of great and detailed comments here seem to focus more on Hancock as a person and his personality, rather than anything he’s brought up.

Taking it at face value, maybe no. The guy, I doubt. A lot. But is is really that otherworldly that there may have been a civilization like the Sumerian living and making monuments before the last ice age? After all, had we not invented say plastic, there would be little to show that we were here thousand of years after us. Maybe not Atlantis, but some intelligent civilization that just didn't bother for agriculture for a long time but was a bit more advanced than a hunter-gatherer group. After all if you say there was this group of people who just so happened to invent agriculture, writing and religion all in one blip of history, that's kind of hard to believe. It's like saying America invented the printing press, cars and the internet all by themselves. It's hard to prove after thousands of years with no record, but is it that unreasonable?