Sprawling Mayan network discovered under Guatemala jungle | Hacker News Reader

Sprawling Mayan network discovered under Guatemala jungle

bbc.com

393 pointsrbanffy117 comments

This highly corroborates Charles C Mann's book 1491: https://en.m.wikipedia.org/wiki/1491:_New_Revelations_of_the...

From wikipedia: The book presents recent research findings in different fields that suggest human populations in the Western Hemisphere—that is, the indigenous peoples of the Americas—were more numerous, had arrived earlier, were more sophisticated culturally, and controlled and shaped the natural landscape to a greater extent than scholars had previously thought.

1491 and 1493 were very enjoyable. I'm having less fun with The Wizard and the Prophet

This is not my field of expertise, but why wouldn't we just run LIDAR scans of as much of the earth's surface as possible?

Is it prohibitively expensive at this point? Is the computation [relatively] expensive? Is there a sound reason we don't race to do more?

I get the feeling this kind of data could inspire generations of new archaeologists and historians.

There are also some pseudo-archeological and pseudo-historical claims that might be put to rest (or less likely, cause a revolution in human self-knowledge). Eg: https://en.wikipedia.org/wiki/Bosnian_pyramid_claims

I would also love to see plots like Cahokia (and others like it) scanned: https://en.wikipedia.org/wiki/Cahokia

A few hints from the article: 810 sq miles mapped, a three year project and lidar flying by helicopter. Another giveaway is the search for MH370. In some dimensions Earth is still huge!

I wonder how much city life biases us to think the planet is smaller than it is. Perhaps it explains fears of overpopulation.

To me, fears of overpopulation have less to do with how much of the earth serves as living space, but how much human activity currently impacts nearly every corner of the planet. I think it's plausible that we can lessen human impact without actually decreasing population. Not sure it's likely, though.

I recall a letter to Science from the mid 70s, rebutting The Limits to Growth. I have tried to find it more-or-less lately, with no luck. As I recall, its author argued that the Earth could support well over 10^8 people in Trantor style. He assumed unlimited energy from fusion, and substantial food synthesis. Only humans, pets, crops, livestock, and requisite insects and microorganisms would survive. The planetary surface would support a building ~16 km high. At that height, the surface would be in thermal equilibrium at ~1500°C.

But hey, if that were doable, why not just build space habitat's?

Because it is cheaper and easier to build stuff down here.

Space habitats require thinking in terms of systems, dealing with inputs and outputs. Humans haven't mastered systems thinking yet.

https://en.wikipedia.org/wiki/Tragedy_of_the_commons

I guess. I've been reading Banks' Culture series ;)

10^8 is a hundred million people, so yeah, it's safe to say the Earth can support well over that many humans.

Oops, I was brain dead there. I meant 10^11. Or maybe even 10^12.

In other words 100 billion to 1 trillion. The world’s land area, excluding Antarctica, is about 50 million sq. miles. With a comfortable population density of 1000 ppl/sqm (like in South Korea, Holland, Israel, or the state of New Jersey) you would get to 50 billion (same as Trantor). The population density of Singapore is close to 20k ppl/sqm, that would give you 1 trillion.

If you are willing to pad the Earth with buildings 16 km high, you could pack at least 1000 times more people, more likely 1 million times more.

Maybe that letter to Science mentioned 10^18?

I don't remember the number. What I recall is just that it was an absurdly huge estimate. And I'd love to have a copy of that ~1975 letter, if anyone has access to requisite tools.

And, in case it's not obvious, it's not a world that I'd care to live in.

Overpopulation at a certain level of consumption is a valid concern.

If all 7.4 billion people on the planet all consume 3 burger patties a day, all drive internal combustion powered vehicles, and all have a new iphone each, that would very quickly require an extreme amount of resource consumption - it is unsustainable.

Of course, if you just want "as high a population at any cost" the earth can probably sustain trillions of humans, but the bulk of those humans would have no clean water to drink, with no access to clean air, no access to a livable wage, no reasonable access to hospital and emergency services, etc.

You could have a trillion slaves, all pampering the lives of a the select few hundred billionaires who own everything. That's the real fear of overpopulation.

It’s both bigger and smaller than we often think.

In a straight line, it’s smaller than we might expect: People can (and do) walk across continents, sail across oceans in one-person boats, fly all the way around in 2 days, visit every country at least once during their life, etc.

But of course the surface is two-dimensional, we can’t see very far at a time. The land surface is about 150 million square kilometers. (For reference, New York’s Central Park is about 3.4 square kilometers.)

It’s also “fractal”, in the sense that as we look at smaller and smaller pieces, we keep noticing more and more details. Every little patch of soil is teeming with tiny animals, plants, fungi, and bacteria.

Or if you like, there are probably at least 10 million restaurants in the world (maybe an order of magnitude more, it’s hard to guess). If you eat at 3 different restaurants every day for your whole life, it will take more than 100 lifetimes to eat at all of them. Then there are the 150 million books to read. Etc.

I would say quite a lot.

A private small-aircraft flight over any populated area (other than the biggest cities) reveals just how sparse most towns are. Travel almost any direction away from a main highway and in a minute or two you'll be looking at trees, trees, trees (or desert/mountains/fields).

It helps give one an entirely new perspective when we're used to traveling along roads and seeing unyielding flows of civilization, when the reality is those are mere ribbons of development criss-crossing what is still mostly empty, disinterested nature.

Ahem, but the trees you then see are usually very civilized ones. Cultivated and harvested like an ordinary field.

There are very few wild areas left. Usually only at far off areas or very steep terrain.

see also:

https://xkcd.com/1338/

Where do you live? I live in the Pacific Northwest and the forests around here are definitely not cultivated.

For scale, the Amazon jungle is a couple million square miles.

I guess I'll just have to study up on the tech. IIRC there was a fairly quick LIDAR demo put on by a team at MIT that scanned the campus and surrounding areas in a relatively brief amount of time using a drone, I think.

My ignorance on the subject of LIDAR has me wondering why we can't use a faster traveling vehicle, or would it be possible to do perform scans with something like a fleet of balloons that stream the data back vs one static device.

Some rudimentary googling, MIT campus is 168 acres or .26 sq miles. So the 810 sq miles in 3 years is still pretty impressive.

MIT also has wifi. And power outlets.

LIDAR data requires precise location-information of the scanning-device, otherwise the data you collect is at best useless, and at-most wildly skewed. This is because all the points are in-reference to the location of the device. A faster traveling vehicle inherently means less-accurate location measurements.

Can SLAM be applied in this case?

It definitely can, though accuracy would always be a big concern.

IIRC, the Google self-driving car used LIDAR. Though their localization algorithms included many sensors, with the LIDAR data was just one of them.

LiDAR collection is pretty dense from a data perspective. When I was working with helicopter collection teams we would regularly collect 1TB of point data per day at around 120 points per square meter. Based on the density of the canopy in Central America, the teams are probably using a density greater than that, and are using "multiple return" depth mapping so that they can see through the forest.

Processing LiDAR data is also quite expensive in terms of the hardware required and expertise of the people needed to correct the data back at the office. Typically LiDAR processing workstations have around 128-256 GB of RAM and a large RAID array of SSDs to quickly perform corrections interactively.

After the initial correction, most of the data is thrown out or "filtered" down to just the points of interest to save on space. Since it's quite easy to end up with hundreds of TBs worth of point data within a few months of collection. If the team is using colorized LiDAR, orthographic, and oblique images then that can take up even more space.

So the short answer to why more of the world hasn't been mapped with LiDAR techniques is money, time, and storage space. But with self driving cars now making LiDAR more prevalent, and storage space becoming more affordable every year, mapping whole regions with LiDAR is a more reasonable task.

NOTE: One of my former jobs was working with aerial LiDAR collection teams to manage the data and processing of the collected assets. This was around 2012 so some of the numbers may have changed since then.

Perhaps neural networks can help with filtering and segmenting the point clouds as well?

Thanks, this is the kind of information I was curious about receiving in a concise digest.

So ultimately it sounds like I have to wait a decade or so before we can really proliferate, and to speed it up need a few more eccentric billionaires to get into funding some cool projects.

I'll use your information as jumping points to find out more.

My hopes lie with the open sourcing of in-vehicle processing hardware and software that is being used within self driving cars. As of today my understanding is much of that is part of the "secret sauce" of companies like Waymo and others.

If it were possible to apply kinematic geo-correction along with point filtering and feature detection during collection then a lot of the "heavy" data could be reduced down to what is just needed for human verification.

If you want to start your investigation with existing projects you could have a look at what the United Kingdom is doing with their government LiDAR data sets[0][1].

[0] https://www.gov.uk/government/news/environment-agency-uncove...

[1] http://vterrain.org/Locations/uk/

Brilliant! Thank you. I wonder now if Canada has any projects remotely similar occuring

Maybe the technology will become accessable enough that everyone with a smart phone can start finding and destroying archaeological sites.

Well, username kind of checks out.

I like the tech because of its ability to prevent the destruction of archaeological sites while still allowing for discovery that would otherwise require an immense amount of digging and other labours.

If my hasty math is in the ballpark, the raw data for 500 trillion square meters would be a few hundred petabytes. Not cheap, but cheap enough that I would guess the cost and logistics of acquiring the data are much more of an obstacle.

Yes that is true, logistical support and processing have considerable costs. For aerial LiDAR collection via helicopter you're looking at about $20,000 per day of onsite collection including the helicopter team, insurance, and support. That gets you high density low altitude assets, not including the processing and storage costs.

It's cheaper to fly with a fixed wing aircraft, but you will typically get lower density assets and the possibility of obscured imagery due to cloud coverage because of the higher collection altitude. However the advantage is you're able to cover a wider collection swath with each pass, and it's a lot easier to fly a fixed wing vs. helicopter so the pilots are cheaper.

How much would the total weight be for the lidar equipment? I wonder if drones would be able to significantly reduce the price.

Met a Cal archeology ass’t prof doing this, quadcopter-mounted lidar.

That depends a lot on the density of point coverage you need. Most LiDAR receptors weighed between 100-300lbs five years ago. They have become much smaller now, again due to self driving cars. However I am not sure that the hardware which is suitable for self driving applications would be "survey grade" appropriate for forest canopy and ground truth mapping. I'm also not sure what the power requirements of the newer LiDAR arrays are, but the weight for batteries is significant as it directly impacts your time "in the air" between ground support stations. In a helicopter you can power all the instruments off a DC power supply from the turbine.

Also typically you want an absolute vertical accuracy of +/- 5cm during flight in order to confidently map the surface features below foliated vegetation cover. This requires quite specialized differential GPS equipment as well as a radio/cellular connection to a commercial GPS ground station network. With the improvements in GLONASS/GALILEO constellations maybe the ground networks are not as critical anymore.

In addition to what everyone else has said: even if we did we wouldn't necessarily know what to look for. I have a friend who's PHD is trying to figure out what ancient dams look like in order to find sites of ancient agriculture. But that's the thing "what does a 500 year old dam look like" is a lifetime worth of study and is only just now possible.

"Just scan the fuck out of it and look for wierd stuff" is the dream but at the moment (as the other comments point out) we can't just scan everything but ALSO we don't know what's wierd.

> In that Empire, the Art of Cartography attained such Perfection that the map of a single Province occupied the entirety of a City, and the map of the Empire, the entirety of a Province. In time, those Unconscionable Maps no longer satisfied, and the Cartographers Guilds struck a Map of the Empire whose size was that of the Empire, and which coincided point for point with it. The following Generations, who were not so fond of the Study of Cartography as their Forebears had been, saw that that vast map was Useless, and not without some Pitilessness was it, that they delivered it up to the Inclemencies of Sun and Winters. In the Deserts of the West, still today, there are Tattered Ruins of that Map, inhabited by Animals and Beggars; in all the Land there is no other Relic of the Disciplines of Geography.

for those (like me) wondering where this wonderful passage is excerpted from:

https://en.wikipedia.org/wiki/On_Exactitude_in_Science

""On Exactitude in Science" or "On Rigor in Science" (the original Spanish-language title is "Del rigor en la ciencia") is a one-paragraph short story by Jorge Luis Borges, about the map-territory relation, written in the form of a literary forgery."

I'm reading this now and it's excellent. It has the important characteristic so many popular revisionist histories lack, restraint. Later day American archaeology practically oozes with opportunities to speculate. Actual physical discoveries beg to be contextualized by our modern imaginations. Mann does visit some of these tangents of the imagination but he is also very careful to bracket these with explanations of what is known for a fact and what is not.

Mann does pick the most optimistic ranges of estimates to try to paint a particular narrative, but he is also very frank that he is doing that, and he repeats this fact several times throughout the book. It would be wonderful if more books were willing to do that sort of guarding to emphasize how much the evidence really supports the thesis. Considering that pre-Columbian America tends to get the short-end of the stick in history, I'm willing to tolerate the constant pushing on the narrative to help emphasize that the popular view of pre-Columbian American is more often incorrect to correct.

1491 is great. It's twelve years old now; I keep waiting for a similar book updated with new scholarship. Things are changing fast.

Please use desktop (not mobile) links here, e.g.

https://en.wikipedia.org/wiki/1491:_New_Revelations_of_the_A...

> Charles C Mann's book 1491

That's not the guy though putting forward the claim that Chinese admiral Zheng He made it all the way to America?

I appreciate the efforts and tech used to map the area and create the graphics but I've been to Guatemala and I suspect that these scientists didn't "discover" near as much as they claim here.

Mayans still live there, and they know every nook and cranny and tree and rock in those forests. If you ask them, and then shut up and listen, they'll tell you all about it and answer any questions you might have.

I did ask one about what was hidden in the forests below us that I met on the top of a pyramid in Belize. He pointed out the locations of about a dozen pyramids in Guatemala that we could see in the distance and told me about the roads and platforms and other structures hidden in the forests around us. I was astounded with what I learned from that man. He was a Forest Ranger who grew up there. His family had been living in the area forever.

I also asked him what they thought about scientists from foreign countries who come there and then announce to the world they've "discovered" something. Suffice it to say this piece would probably irk him because it pretends none of them knew anything about most of what scientists claim to have "discovered". He also opined a bit on how their culture has been depicted as being violent and bloodthirsty and offered a much more tempered version.

But, it is nice to know that Guatemala funded the project and have the data. That part is cool as can be and I look forward to hearing more about what they learn from it.

Similar thing in the lower parts of Mexico. As told to me by some locals on a stop while riding through the country on my motorcycle, there are plenty of locally known, overgrown ruins that are yet undeveloped as visitor sites simply due to lack of funds or renovation resources.

Most professional archaeologists/anthropologists do ask the indigenous people and do listen. Sure there are always some people who are attention seekers, but the majority do good science and leverage indigenous knowledge. That said, you overestimate how much the people can know. They don’t have ground penetrating memory, and the Maya people have always been far from one united nation but closer to a collection of city-states with some shared cultural traits.

Furthermore, most of the classic Mayan sites were long ago abandoned so it isn’t like there are indigenous people hanging out around Ti’kal or Calak’mul that can just spill the entire history.

Any competent Mayanist would have told you the same as that person in Belize. It is no secret the landscape is dotted with unexcavated ruins, but the scope is unclear which is exactly why this research is so useful.

"They don’t have ground penetrating memory,"

No, they don't.

I'll point out that the article mentions they "remove the dense tree canopy to create a 3D map". It does not say "they used ground penetrating Lidar".

Seems to me you underestimate what they know and overestimate what you know and that is exactly what I was saying they found irksome.

Reminds me of the recent finding that the Amazon River basin was much more cultivated in the ancient past than was thought:

https://www.theatlantic.com/science/archive/2017/03/its-now-...

Which in turn reminds me of Richard Feynman describing the Mayan Calendar in his famous lectures on quantum mechanics, as an example of how the Mayans understood how the planets moved by looking, that they even figured out a number of patterns and predictions, but that they still did not know why the planets moved as they did, his point being that current understanding of quantum mechanics is very similar to this[0].

At the end, he tangentially mentions that we only know about this calendar because it is described in one of the three surviving books of their culture, out of thousands[1]

> "Just imagine our civilization reduced to three books, just the particular ones left by accident, which ones... So eh.. anyway, I get off the subject..."

The genocide of Native Americans is of course horrible by itself, but somehow this remark made me realize what "genocide" means beyond people being killed en masse. So much culture and knowledge was lost.

[0] https://www.youtube.com/watch?v=xdZMXWmlp9g&t=25m28s

[1] https://www.youtube.com/watch?v=xdZMXWmlp9g&t=32m26s

This is why liberals are sometimes using the term genocide more broadly in a way conservatives don’t like. They reference things like “black genocide” and conservatives get mad because the actual slayings are too few to be considered “genocide”.

Yet in terms of lost culture, putting a high enough percentage of individuals in prison, and confining enough of the others to ghettos, while driving them out of historical cultural centers, has an equivalent result to genocide in some ways.

Essentially, a percentage of the people can be alive while also having “the culture” be as dead as dead can be.

Of course the culture is born again in a different form, as Native American culture endures today, despite “genocide”. And rendering that invisible is just a continuation of that genocide so I certainly don’t want to intimate that such culture is truly gone.

> Of course the culture is born again in a different form, as Native American culture endures today

Well, a culture is born again; culture just tends to happen if you put people together, it's in our blood. The question is whether it flourishes. I am from Europe so cannot say this for certain, but I get the impression that all over both American continents, Native Americans are still very much an ethnic minority whose rights are being trampled over.

In Guatemala, they’re an ethnic majority whose rights are still being trampled over.

And the reason that there are only a few surviving books is that the Spanish conquerors plucked those out to send back to Europe as curios before they burned down all the libraries.

Anything survives in a museum?

As for Mayan codices, only three (The Dresden Codex, The Madrid Codex, and The Paris Codex) are known to survive.

Most of the books themselves were destroyed as the work of heretics, e.g.

https://en.wikipedia.org/wiki/Maya_codices

This stuff drives me so nuts. It also seems to be something that I've only ever noticed being done by religious people who follow done monotheistic believe. Does anyone know if any destruction of a culture and its artifacts had happened by someone not motivated by monotheistic delusions?

It was common in the ancient world -- "we won because our god(s) are greater than your god(s)."

Look at the (pagan/polytheist) Romans' actions in the seige and destruction of (monotheist) Jerusalem, for one example. Or (pagan) Viking raids on English/Welsh/Irish Christian monasteries for another.

Do you consider the Chinese cultural revolution to be the product of monotheistic delusion? What about the more recent Chinese occupation of Tibet?

What about the Nazi party? The Japanese occupiers of Korea and China during WWII?

The British burning the Burmese royal library in the late 19th century? Or the current massacres of Muslims in Myanmar by Buddhists?

The US Army in its genocide of indigenous North American tribes?

My impression is that there are at least some anti-intellectual authoritarians in every country, religion, and political movement.

"Do you consider the Chinese cultural revolution to be the product of monotheistic delusion?"

Yes, actually. The religion was Marxism (i.e., the most murderous religion in history), with Mao Zedong as its Prophet.

There was a interesting discussion somewhere (can't remember where) that called communism the first techno religion. The idea was that everything is build around the expectation that labor will become less important and owning means of production becomes paramount because of automation. Very relevant thoughts nowadays. Nice to look in the mirror of the past.

I highly recommend Eric Hoffer's The True Believer if you're interested this topic at all. It's a short book full of major ideas.

Hoffer's treatment of the phenomenon is just as fresh and relevant today as it was when he wrote the book in the 1950s.

I got downvoted for suggesting that Maoism was a religion, but it quite clearly had more commonalities than differences with the more extremist religious cults (as did Stalinism, Nazism, etc.)

This was a honest question. With so many atrocities going on it's hard to differentiate which ones don't only seek out to kill all members of a given culture but also their cultural artifacts. Thank you for listing several that fit the bill.

That’s exactly what I just said... the Spaniards burned all of the books except for a small handful which were sent back to Europe as curios.

> We found a large number of books in these characters and, as they contained nothing in which were not to be seen as superstition and lies of the devil, we burned them all, which they regretted to an amazing degree, and which caused them much affliction. – Bishop De Landa

Once again someone many have accused of tinfoil battery being shown to be onto some nugget of truth. He had a medical scare recently, anyone know how he's doing?

I have trouble seeing the connection between your reply and my comment - did you intend to post it elsewhere and did it accidentally end up with mine?

EDIT: My best guess is that this was intended as a reply to https://news.ycombinator.com/item?id=16292738 an referring to Charles C Mann and his book?

Sorry for some reason I misread Feynman as something else...

There have been quite a few crackpots saying ludicrous things about the Mayan calendar, so that sounds like understandable mistake to me.

I'm reading "Lost City of the Monkey God" by Douglas Preston right now. It's been a highly entertaining first-hand account of (what I think was) the first use of LIDAR for archaeology in the jungles of Central America, and the ground exploration that followed. I'd definitely recommend it to anyone who's interested in this story.

https://smile.amazon.com/dp/B01G1K1RTA

You might also be interested in "Breaking the Maya Code" which is a great historical account of the decipherment of Maya script.

https://www.amazon.com/Breaking-Maya-Code-Third-Michael/dp/0...

I loved this book! I think any software engineer would enjoy it.

I just started reading this book last night (my wife listened to the audiobook version several months ago, which caught my interest). Strange how these things "come together"...

That's more of a reflection of how big HN has become than anything else.

I appreciate you using a smile.amazon link.

I'm guessing you were downvoted by mistake.

The smile links are not affiliate links for individuals, they are for directing part of the proceeds to the specific charity of the buyer's choice.

The is one thing I don't understand. The article reports the use of lasers to map the ground, yet they mention the presence of foliage in situ. Assuming that they use optical or infrared lasers, foliage should be completely opaque at these wavelengths. How did they manage to map the asperities and characteristics of the ground?

A filter that takes the most deepest z-value you get, considering all else in a square meter as noise- or foliage?

LiDAR wavelengths are returned at various depths from within the forest canopy. In order to get a return on the ground you simply filter the returns down to the last value.

Sometimes however you want to keep the other returns and so you filter the values down to say 10% of all returns from a given depth, with a constraint between the depths of say 10cm so that you can see the density of the layers.

You see overgrown mounds all over central america, and not all of them are volcanic. There's an immense amount of undiscovered history there.

Yeah i think we are heavily underestimating how quickly nature can retake cultivated land.

This is something that has always fascinated me - just how do the processes which cover a landscape with, say, layers and layers of sediment - or jungle cover - really work?

I mean, I get it - you leave something out, a few weeks later its going to get covered in a layer of dust/sediment. But how is it that entire cities get buried under 10's of meters of dirt? I'm sure geologists have this all figured out, but it always amazes me that our world changes like this so rapidly.

In this case, I'm sure the answer is 'the jungle eats everything' .. but there are places in the world, buried under meters of sand and sediment, that I just wonder .. how does this happen ..

Leaf litter accumulates and breaks down and becomes new soil, mountains and hills erode and that sediment accumulates in lower areas, wind move lots of sand and fine sediment around, All of that piles up in places until things once on top of the soil are now buried.

It's a little more complicated than that, but that's part of the process.

Another aspect is that cities used to literally rise as they deposited waste in situ and had to build up as 1st floors became basements. This is partially the source of mounds.

Neat reddit discussion: https://www.reddit.com/r/AskHistorians/comments/17je7i/arche...

Yeah, same here. And some ancient cities and settlements have _layers_ below them[1]. How?

[1]https://en.wikipedia.org/wiki/Troy#Historical_Troy_uncovered

Archaeologists have characterized various layers, the depth and thickness will vary.

So a layer there might just consist of evidence of some particular activity that one settlement engaged in that earlier and later ones did not.

It's not that complicated. Humans tend to build in flat areas. Flat areas tend to be flood plains. When flood plains flood they leave behind sediment. There are additional ways that sediment builds up such as airborne deposits and importantly from growing plants leaving behind biomatter, but in a lot of cases flooding explains the substantial depth of sediment deposited.

It’s one of those overlooked facets of Nature. Much of the Great Plains sits on the Ogallala Aquifer. This is an underlying terrain, to depths of hundreds of meters, filled in by sediment from the Rockies (https://en.m.wikipedia.org/wiki/Ogallala_Aquifer#General_cha...).

The greater part of the LA Basin is a floodplain which consists of hundreds of feet of sediment from the San Gabriel mountains.

There are lots of depositional (and erosive) processes happening. They're all subject to local conditions. But the most common (in no particular order) are: accumulation of plant matter, flood deposits, human-generated organic and building debris, and earthworm casts. You can also see other things, like volcanic activity and wind-blown material, in fewer places.

In some hiking circles you see people posting pictures of basements or fallen chimneys in the middle of nowhere in a wooded area.

If you passed more than fifty feet away you might miss them.

Definitely. It's a common sight in tropical countries to see modern buildings covered in random growth foliage (gutters, roofs, pavement cracks, window sills, etc.). I'd hazard a guess that even 20 years would probably be enough to significantly hide most low-rise buildings.

This is an astonishing thing to witness. Many people are familiar with the well known sites, they have seen the temples in pictures or on a TV show, for example Tikal. These sites are commonly depicted after they have been painstakingly reclaimed from the jungle, the structures are stone colored and the paths among them are dirt brown.

What's not commonly seen is the view out from atop one of these tall structures - the chaotic green sea of the jungle canopy is punctuated by tidy triangular mounds as far as the eye can see. The landscape is littered with these structures that were once upon a time built and maintained by many generations. Weep ye mighty!

There are two NY articles worth reading: https://www.newyorker.com/magazine/2013/05/06/the-el-dorado-... and https://www.newyorker.com/tech/elements/an-ancient-city-emer...

The better link for Americans is here on National Geographic: https://news.nationalgeographic.com/2018/02/maya-laser-lidar... It lists a special including the Lidar discoveries on Feb 6 on National Geographic.

The NatGeo submission was a good read too:

https://news.ycombinator.com/item?id=16286230

Direct link:

https://news.nationalgeographic.com/2018/02/maya-laser-lidar...

Is that possibly a meteor crater seen on the right of the second LiDAR picture?

You mean the left side?

The link below may be interesting to look at (or laugh at?) since the LDS church's famous book claims to be about 3 civilizations that lived somewhere in north,central or south america. As far as I understand, one or more LDS leaders years ago decided (for arguably valid reasons) that all of the Book of Mormon events occurred between 600 BC to about AD 400.

This has made it more difficult for the church to say "look, we were right!" when discoveries like this are made because the timeline in several cases doesn't align with 600 BC to AD 400.

https://en.wikipedia.org/wiki/Archaeology_and_the_Book_of_Mo...

The Book of Mormon never claims that everyone died in the Americas at AD ~400. Nor does it claim that its account of the peoples there is comprehensive. In fact, it says the opposite: that splinter groups settled elsewhere, that there were other bands of people in the land, and that after the destruction of the Nephites, the millions of remaining Lamanites continued to sprawl over the land.

And it also says things like horses, chariots, steel, and other anachronistic things existed in the pre-Columbian Americas. There is no evidence (to date) to support any of those claims. You might want to look into the history of NWAF and Thomas Ferguson. Michael Coe, a renowned expert in this field and also mentioned on this post, was friends with Ferguson. It's an interesting history.

> And it also says things like horses, chariots, steel, and other anachronistic things existed in the pre-Columbian Americas. There is no evidence (to date) to support any of those claims.

Horses definitively existed in (far enough) precolumbian America. The dominant belief seems to be that they died out (perhaps due to human hunting) at or shortly after the end of the Pleistocene, ca. 10-12kya, but there is some evidence there may have been some populations around as late as ca. 3kya, IIRC.

EDIT: of course, one must keep in mind that the horses of precolumbian America were much smaller than Old World horses, so it's not really plausible that they'd be being ridden, pulling chariots, or generally being used like Old World horses even if it is (just barely) plausible that they were around at the right time.

I should have qualified that with "during the Book of Mormon timeline".

3kya is just about at the Book of Mormon timeline.

Just about is fair but still short by ~400 years, unless you count the Jaredites. They purportedly fled the Old World around the time of the Tower of Babel (~2000 BCE IIRC?).

EDIT: I wasn't sure if the Book of Ether even mentioned horses, but it did, along with elephants. [1]

[1] https://www.lds.org/scriptures/bofm/ether/9.19?lang=eng&clan...

Could it be that maybe some things were lost in translation? Maybe a “chariot” isn’t exactly the way we think of a chariot now. Maybe it was just a saddle?

You might want to look into the loose vs. tight translation theories. There are resulting consequences with sticking with either one.

John Sorenson ( Professor of Anthropology at BYU) addresses most of your speculations in this article. I found his responses very well written: https://www.fairmormon.org/archive/publications/an-open-lett...

There certainly is, you just have to look for it. https://bookofmormoncentral.org/blog/new-evidence-for-horses...

> While the evidence for horses in pre-Columbian America is encouraging, it still requires some caution. Additional C-14 dating from other samples will be needed to change the prevailing view. Until then, this evidence should be considered provisional, but promising.

And was that peer reviewed?

You may find the responses in this article intriguing: https://www.fairmormon.org/archive/publications/an-open-lett...

Not being critical, only pointing out every time their is a big discovery like this, some level of time and effort is spent trying to align the discovery with the BOM. The wiki article has a lot of references in it that are related to the topic.

You might enjoy this recent Science story:

"How a Mormon lawyer transformed archaeology in Mexico—and ended up losing his faith"

http://www.sciencemag.org/news/2018/01/how-mormon-lawyer-tra...

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