Building Movable Stone Walls with pre-20th century technology

In many movies about ancient Egypt (most recently perhaps The Mummy and it’s sequels/spinoffs), in National Treasure, in many Clive Cussler caliber adventure books, etc., treasure hunters come across a stone wall that when an ancient key is inserted (an ankh, a carving, etc.) the wall moves away to reveal a hidden room.

Out of curiosity, would there even be a way to conceivably build a room that would do this? What would you use to move the walls?

While I doubt anything like this exists, what are some of the more ingenious actual bits of pre-modern architecture you’ve read about involving architectural secrets?

I’d use raised weights to provide the motive force, because they are ancient technology and because gravitational energy isn’t going to dissipate over time. I’d make hinges and linkages and rollers out of stone or maybe gold, because they won’t deteriorate. I’d use graphite on friction surfaces because it doesn’t deteriorate and (I would think) would have been known to the ancients. I’d overengineer the thing to hell to allow for the mechanisms grunging up over the centuries. Then you need to build the thing into a structure that is very water and dust tight because they are going to be the enemies of your mechanisms over time.

Actually, hydraulics would be your best bet from a simplicity standpoint; mechanical linkages and pulleys are going to tend to bind up over time and a complex system is going to have significant mechanical inefficiencies. The problem with using gold for rollers and linkages is that it is soft. There were harder metals, such as bronze, that don’t corrode as readily as steel; this is assuming a Bronze Age civilization (Byzantine Eurasia, perhaps). The Incans and Aztecs, lacking iron or significant (accessible) deposits of tin, wouldn’t have built large metal structures and machines, and is probably one reason why their technology was not as advanced as the Eurasians despite their extensive pre-Colombus civilizations.

I don’t believe that pure graphite was known to any pre-Industrial civilization in any significant quantities. Talcum would be a fair dry lubricant, but is hygroscopic and thus wouldn’t make a good long term lubricant. I think you’d just have to design to accomodate and minimize friction.

The ancient booby-trap devices of Hollywood films (a light-triggered spike-frame?) are purely the invention of imaginative screenwriters. However, an example of a real-life booby-trap can be found on Oak Island. It’s ingenious (though dependent upon the ignorance and destructiveness of a potential thief rather than great mechanical complexity) but nobody really knows who built it and what, if anything, it contains.

What I want to know is…how did Indy survive a several hundred mile journey on a submerged submarine?


Disagree. Water is too unpredictable and reactive. It seeps, it evaporates, it corrodes. If you build the thing with a captive water reservoir I think the chances of that water still being in place without having leaked or evaporated away in a couple of millenia are next to zip. If you rely on an external source (a lake or a stream) the chances that it is still there and not silted up or whatever after a couple of millenia are similarly zip.

I agree that linkages are going to tend to bind up, but that’s why I’d overengineer it to hell: use a 10 tonne rock to move a 1 tonne door, so that it just forces linkages despite them being grunged up. And use linkages that are waaay stronger than you would usually need so they don’t break when subjected to high forces.

I know gold is soft, but it’s not butter: as long as you don’t use it for something requiring it to be hard, it’ll be fine.

I’m guessing, it didn’t submerge. But we don’t know for sure, do we?

I don’t know about modern day submarines, but older ones used to travel faster on the surface.

jus my two pennies worth…

such ‘movement’ of ultra heavy doors could actually be a ‘slide’…

if the door is slightly slanted/angled, gravity might take care of the rest.

Of course, the ‘slide’ would have to remain blocked (till the block is removed by the key or combo or somethin similar)

Its Conceivable… definitely.

In the scene right after Indy is spotted on the sub’s deck by the cargo ship’s crew, the sub’s skipper appears to be giving diving orders.

Perhaps they dove to periscope depth and left the periscope up, and Indy, using his whip as a ski rope…never mind. :smiley:

“Dr. Jones? Your persistance surprises even me. You’re going to give mercenaries a bad name.”


It’s cute moviemaking, but don’t confuse it with reality. Ancient moving contraptions look great on screen, but I can’t imagine them continuing to work in real life. Whenever you find ingenious mechanisms in real archaeology, they’re either fused together, or have to be reconstructed. The Indiana Jones/Goonies/The Egyptian/The Mummy kind of still-working mechanisms are ludicrous if you give them a moment’s thought. The best I can think of would be delicately-balanced constructions, perhaps with a counterweight, but these would bind up easily unless constantly lubricated and “worked”.
Incidentally, most of what’s been written about Oak Island is highly suspect. I wouldn’t really count it as a example of this kind of thing. (And even in the story as usually told, there aren’t any working mechanical devices – layers of cocoanut matting and water tunnels, but no swinging doors). If you want to get your jollies with an Oak Island-style situation with working mechanical traps, get yourself a copy of Douglas Preston and Lincoln Child’s book Riptide: Obviously inspired by Oak Island. Ludicrously over-the-top (like theor book The Relic). but a fun suimmer read.

  Yes, but on the surface there would always be crew in the conning tower, or on deck.

   I have always had a problem with this scene, not only because of the submerging problem, but because of the simple fact that a U-Boat is a confined, crowded space, there really isnt any way that a man could stow away on one for any period of time and not be seen by the crew.

Which is why Spielburg cuts away to a red line on a map. :smiley:

I guess it’s kind of a pointless gripe given the vast number of improbabilities and unexplained movements (how, exactly, do Indy and Marion get the Ark off the island?) but that one has always struck me as particularly absurd. But then, that’s the fun of Raiders; it doesn’t slow down long enough for you to have to think through these things, and it is satisfying enough in every respect (humor, action, character development) that it doesn’t detract from the enjoyment.


In a movie full of ludicrous improbabilities, it’s absurd to single one out, I’ll agree.

Unless it undermines your suspension of disbelief. Then it’s a killer, and deserbves to die. This is what that submarine thing was to me – I know, intellectually, that subs would prefer to stay above water and use their diesel engines, rather than submerge. But I can’t help thinking that “It’s a sub. If it goes under, Indy’s screwed!” The fact that I’m thinking about it at all is a fatal flaw in the film.

I felt the same way about the “jump out of the airplane in a life raft” openinmg of the next film. It’s hard to appreciate the movie when you’re convinced everyone in it ought to have broken necks and multiple broken bones.

The thing with a pulley system isn’t the pulleys themselves. I imagine one probably could overengineer them sufficiently. What I want to know, though, is what are you using for rope? I can’t think of any fiber known to the ancient Egyptians which would survive for millenia, even in a desert climate. Silk, maybe, but I’m not sure if it was even available to the Egyptians, and if it was, the required quantities would be hellaciously expensive (even by Pharoic standards).

If one insists on a moving wall, I think the simplest course would be for it to just move straight down. Have some sort of supports that are released at the appropriate time, and it just falls.

The scene that sticks in my mind is the one in the 1956 the Ten Commandments, where an ambassador brings silk to Rameses II. No one knows where it comes from.
So I googled, and found this:

If true, there was silk in Egypt by 1000 B.C. But not a lot of it, evidently. Not enough for ropes, most likely.
I think you could have pivoting and falling rocks, but I wouldn’t want to have to depend on their integrity. (see the old movie The Egyptian for descending rocks, controlled by falling sand. Or the recent remake of The Mummy.)
I still want to know where the ancient South American Indians got the light sensors they used in the trap that killed Forrestal in Raiders of the Lost Ark.

Or descends in a controlled fashion, sitting atop sand now pouring through a smallish hole into a chamber below. If it’s set up just right, you’ll have just enough time to grab your hat before the descending wall hits the floor. :slight_smile:


Did The Egyptian have the falling rocks via sand mechanism? I thought it was Land of the Pharaohs, with the young Joan Collins on the wrong side of the wall. It’s been a long time since I’ve seen either picture, so I could easily be wrong.

You’re correct – my memory was playing false with the name.

“He was good. Really good.”

I want to know how they maintained pneumatic pressure to power those darts for hundreds of years…and why, despite their mechanical ingenuity, the dart-shooters weren’t any more accurate than SW stormtroopers.

And, if there was an opening at the top of the tomb (where Indy uses the whip to jump across the pit) why didn’t he just climb down there and bypass the taurantulas, the spike-trap, the slowly-falling door, and the rolling boulder.

And why did he need guides, load-bearers, donkeys, et cetera when he was able to land a sea-plane five minutes away?

And why…oh, never mind. It’s a great film. But it ain’t reality.


We’ve got top men working on it. Top men.

Chains would work.

Well, you could always use sand in some way (though I suppose it might get compacted over time). Basically you fill a hole with sand and at the bottom you put in a plug and put your heavy door or whatever on top. Unplug the hole (maybe a simple mechanism to unplug the hole if a ‘button’ is pushed), sand goes out the hole, door opens by slowly descending into the hole. Isn’t this how the Egyptians lowered some of the very large stones into place?

I don’t remember the book now, but one of the ingenuous ancient traps I’ve seen (fiction of course) consisted of an air tight stone chamber that descended into a U shape before rising up again. Fill the chamber with something that releases CO2 (I think they used some kind of plant that would decay…this is all from memory of course as I can’t even remember the title of the book). Since CO2 is presumably heavier then air, and since the chamber is air tight, it will sink into the U bend. When your intrepid treasure hunters come in and descend into the U they quietly suffocate. Least, that’s how it worked in the book. :slight_smile:

Aren’t there supposed to be all kinds of traps in the pyramid of the first Emperor of China’s tomb? I know they haven’t really begun to seriously excavate it yet, but I remember reading that supposedly there are all kinds of sophisticated traps and such guarding the tomb, which is one of the reasons, it (supposedly) hasn’t been looted.