How to build a trap to last the ages?

Question

While considering Ancient Light Trigger Mechanism, it occurred to me that any ancient trap mechanism is unlikely to work very long without regular maintenance. It seems far too easy for dust to clog the triggering mechanism, or for animals to burrow close enough to the hidden mechanisms to disrupt them, and for any organic materials to rot.

How do I design a trap to last the ages? My (eventually) ancient ruin isn't going to protect itself without them!

The traps need to:

• pose a legitimate threat - a dart-shooting trap that has lost most of its strength and shoots a dart without enough force to penetrate skin is a no-go.
• be reliable - a practically unavoidable trap that causes injury is better than an easily avoidable trap that kills you.
• last as long as possible - a broken trap isn't really a trap at all.
• bonus: being able to use the trap more than once

I'm going to open this up to all levels of technology - I'm curious to see if someone can figure out how to do this with ancient technology, but this seems like it could be challenging to modern technology as well.

Answer 1

A simple pit trap.

Have a simple pivot counterweight trapdoor that resets the trapdoor after someone falls in.

The parts are simple and would last virtually forever. A build up of dust would actually help camouflage it.

A (very) simplified diagram:

Answer 2

Radiation The trap that keeps on trapping! Just powder your passageways with large quantities of plutonium dust.

Then you and your comrade can come and go as you wish, simply by donning lead-line clothing and sealed breathers. Would be thieves and future archaeologists probably wouldn't think to scan for radiation until after finding the bones of their predecessors. And by then, it would be too late.

Answer 3

Gas

If your structure is underground with limited ventilation and built over a geothermal vent releasing carbon dioxide, the chambers would be filled with an odorless unbreathable gas. Our intrepid tomb raiders would just have time to wonder why there are all these desiccated corpses lying about before losing consciousness.

Likewise if the vent was releasing hydrogen sulfide, there would be a foul smell around the structure (explained by local legends of a "curse") but at the higher concentrations inside, the smell would seem to disappear. People would die before they even realized they were in danger.

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Afterthought edit: Hydrocarbon gases (methane, ethane etc.) are not only asphyxiating but they can cause fun explosions when Prof. Jones turns up with a naked-flame light.

Answer 4

Troll the dungeon raiders

Death is just too liberating. Whether it comes fast or slow, it will lift you out of your suffering.

Psychological damage, though, can last for multiple incarnations.

Make sure your dungeon is empty, then paint "overthinking" on a wall. Watch all the strife that it will cause.

Source: Oglaf. It is a webcomic with usually NSFW content, so I will only mention it rather than linking directly.

Paint can last for millenia, as the egyptians have shown us.

Also notice that past a certain technologic level, people may start endless discussions about the meaning of the trap. Some of these discussions will end up in invocations of Godwin's law, or escalate all the way up to threats of physical violence - thus extending the damage caused by the trap not only through time, but also through space.

Answer 5

Tar pits

Why invent a new trap when nature has one that it's been using for thousands of years?

And they're self concealing! A few years of dust and no one will ever suspect that the bones of a few dozen explorers lie beneath their feet until it is too late.

Answer 6

High tech: Fizzled atomic bomb.

Above the trapped door is a tube full of beads of some kind (sand would even suffice but I think it would be more likely to leak out over time.) They are held in place by the door, open the door and they pour out. They were holding up a cylinder of fissile material, it's lowered into a ring of it. The resulting mass is supercritical. U-235 or Pu-239 are both acceptable, U-235 will last longer before decaying.

Assembled this way you're not going to get much of a boom at all--it won't even blow up the room, let alone the whole tomb. The person who opened the door will still be alive afterwards--for a very short while.

Dry, geologically stable and well sheltered from wind-blown dust I could see such a device being operational for many millennia.

Answer 7

Something biological is likely to have a fair chance of surviving the ages, as they have the advantage of being "self maintaining".

Put your temple in the jungle, create the ideal habitat for very venomous / poisonous frogs, snakes & spiders within several chambers and it should be good for a few 100 - 1000 years. Suppose it is unlikely to catch everyone, every time, but should see a decent mortality rate for small parties exploring.

Answer 8

Spores

There are some nasty fungal spores that will give any intruders a hard time in the weeks that follow their attempts to disturb your treasures. They could wander around carefully but once they start trying to move anything they'll disturb the spores and trigger the curse. "Look but don't touch".

This will keep on making people sick for many visits. Assuming that there are also some heavy-duty doors involved in the design, and maybe some tight squeezes, it could be difficult to get through without disturbance or exposure.

These spores can last for millennia at least, and can't be detected at a distance (unlike say radioactivity).

Answer 9

Use the tide

Build your structure between sea level at high and low tide. Build it inland, far enough from the sea for the tomb raiders not to think of the sea. Build a tunnel between your structure and the sea shore. Make the path in your structure long and flat enough to make outrunning the tide impossible.

At every high tide, any intruder will be drowned. The whole structure can be considered as the trap.

Low tide

High tide

Advantages:

• No mechanic
• No maintenance
• Reusable about twice a day
• The water will wash away the corpses, leading the visitor to think nobody died there before, and that it is hence a safe place.

Disadvantage:

• Somehow difficult to build a tunnel that last long (but if your structure does, I don’t see why the tunnel wouldn’t)
• Pretty obvious (“Hey guys, it’s full of dead fishes in there, I wonder where they came from?”)

Make it more lethal (but harder to build and maintain):

• Floating door, so only possible to enter at low tide, hence not noticing high water on arrival. Or other floating mechanism that delay going down while the water is high, so the explorer will not notice the water until it starts to go up. For instance a floating door hiding stairs.
• Make some siphons, blocking retreat
• Make a vane so that the water going down is slower than going up. So even if the intruder see the water when it is recessing, he/she is going to think “if it goes slowly down, surely I will be able to outrun it when it goes up”.

Answer 10

Make the door part of the structure

Design your building with a really obvious doorway. Label it with all sorts of do not open signs so they really know that this is the way you get in. When an aspiring tomb raider breaks down the door, the whole roof falls down on him. Make sure to give it enough margin of error that it won't just fall over the next time there's a big thunderstorm.

I say door, but this would probably be more like a seal than a door. You would have to break it to get through.

Answer 11

Event Horizon

Nothing lasts forever, including black holes, but they are zero maintenance and they are indestructible.

We at Event Horizon Traps® guarantee they might get in, but they ain't getting out ! Your money back if we're wrong.

So ("any level of technology") we can say a Kardashev level 2 culture might be able to construct custom black holes or more complex event horizon based "structures" which cannot be unlocked and can exist for arbitrarily long time frames.

Even when they decay by Hawking radiation (which we'll assume exists), nothing is left behind (including nothing nearby as the end stages of evaporation will be an explosion !).

Answer 12

"all levels of technology" - you say?

So how about nano-repaired guardians powered by a renewable source of power (sun, geo-thermal, etc)?

Hell, you could even make the nanobots your trap - unless you're wearing a "friend" amulet or something, they will infest you and turn you inside out; "what's that black vein-like coloring spreading from your fingers up your arms after your just touched that glittering, nice statue?"

Answer 13

A: Curtains dusted with cyanide powder. Moving through them puts cyanide dust in the air. If you use the right fabric, probably get a dozen uses.

B: Sealed bottles labeled "Ambrosia of the Gods" Contents are something like ethylene glycol (tastes sweet) and lead acetate (also sweet.) And of course alcohol. The beverage is designed to taste sweet. Nearby you have the food of the gods, which is salty enough that it encourages people to drink. (Glycol has been used in wine to make it taste better with lethal results.)

C: If air circulation can be restricted enough, a heavy gas such as per-fluorbutane or sulfur hexafluoride. Both are non-toxic, oderless, stable gasses that are several times heavier than air. A smothering gas is wonderful for this, as it doesn't interfere with breathing. You don't feel any distress because you can still get rid of CO2 easily. But over the course of about 5 breaths, you no longer have any O2 in our blood. But you've passed out.

Scenario. A set of stairs that descend down one side of the chasm and climb the far side.

"I smell a trap! Let me go first." Walks down the stairs. Gets about 10 steps down, and keels over. His two companions rush forward. Join the unconscious. After a minute the heart stops. After 6 more, brain death.

The downside of this one is the litter of bones on the first landing.

You can also use this a fill gas for any room with an airtight door. Works especially well if the room is at the bottom of a stair. In any case the room should have several times the volume of the ante-room as you might get a situation where the bottom 3 feet is unbreathable, while the top air is fine.

C: The ruins are underground, and very level. There is 3 feet of water everywhere. You venture in, but it's a slog. There are too many restricted places to use boats. You hike in, and realize there is no place to lie down to sleep. And you're lost.

D: Natural syphons. At some high place there is a lake. There is a cavern that connects to the lake in a gooseneck, such that the top of the gooseneck is below the max height of the lake. When the lake level rises above the top of the goosneck, the syphon starts, and floods the ruins.

Downsides: Once figured out, you only have to be out before the lake gets that full. But also means that the interesting bits of underground city gets soggy periodically.

Answer 14

With modern technology, you have explosives and landmines.

Landmines already have a proven history of being lethal centuries after being placed. You could use fragmentation weapons, which would more or less leave the Temple itself unharmed, or you could just have an 11,000 lb bomb instead of a rolling boulder trap. Best case: the adventurer makes it to the treasure, and then is atomized immediately and without warning. Worst case: the bomb goes off prematurely, taking the treasure and structure with it, thus preventing the removal of the (intact) treasure.

This is an especially good strategy since many explosives of that age no longer rely on electrical signals, as those have decayed long ago. Instead, the merest suggestion of movement is often enough to set one off, meaning that its trigger is literally tied to the explosive itself.

This also has the potential benefit of being reusable. If cluster style munitions are used, not only is the explosive extremely lethal itself, it has a tendency to spread some of the unexploded material around the trap room(called UXOs). This behavior occurs anyway despite cluster weapons not being specifically designed to do so, meaning trap weapons like these could be designed to last a much longer time, with them also designed to sling UXOs deliberately and in a more calculated manner. So as long as you have some of the original mines still left, you have a sort of self healing minefield. One adventurer could stumble upon the place, trigger three mines and be killed, and the UXOs would spread to cover the same area and kill another adventurer 50 years later.

In terms of ancient technology, I'll exclude magic as it tends to be able to generate plenty of its own handwavium anyway. One of the best ancient strategies is stealth. Placing traps will prevent access to the treasure, but doing so means that any survivors or casualties will be tipped off to the potential value of this ruin. Besides, no self respecting Tomb architect places traps willy nilly.

The ruin being inconspicuous and in a remote place will go a long way to preventing the treasure from being found and will help the traps last longer. (Even the mightiest fortress or the cleverest trap will not last forever against a sustained assault.) Having a fake treasure room with a few traps and a significantly less valuable treasure is a good way of faking out adventurers into thinking they have already found the treasure. As for secret doors and fake walls, its almost better to adhere to K.I.S.S. Instead of secret doors, just wall it up solidly. Adventurers cant find a secret passage if there isnt one. Most people won't bother mining through the wall if its plain, thick, and they've already found the "treasure".

Besides, 6000 years later when your Lich-y self decides to go and retrieve the treasure for whatever reason, youll have a strong knowledge of the traps and a few walls won't really hinder your progress if you know where to dig.

Answer 15

I would go with a huge maze. It would be a trap on its own, if it is large enough. And you could incorporate most of the other suggestions into it.

Even if one of them eventually stops working, the made would still be deadly enough.

Answer 16

Coal gasification

Naturally occurring coal reacts with naturally occurring water heated by a nearby volcano to produce Syngas to fill the ruin's chambers. When someone carries a flame source and oxygen into the ruin, the Syngas explodes.

This is self replenishing as long as the coal and water and geothermal sources last.

Note: If you accompany this trap with a sprinkle of radioactive particles, then venting the ruin of Syngas becomes a extremely dangerous process as anyone inhaling the particles will get acute radiation sickness

Answer 17

A pit of quick sand will last the ages. Organic matter will dissolve in it as it basically will be very much like a septic tank which can be filtered out with chemicals at the bottom of the pit. It's perfectly concealable in any light condition as long as the surface of the ancient ruin.

• It's self resetting
• Doesn't get effected by time or the elements (especially if indoors)
• Is concealed without the need for a mechanism
• Can kill or at least cause harm where the body is stressed in trying to get out
• It's reliable as it only required gravity and the weight of the trappee
• You can use the trap more than once

Answer 18

Seeing as you open this up to all levels of technology, I'm going to propose a simple pit trap that goes right to the centre of the Earth. There's really not much to go wrong with a hole, and it eliminates a build-up of dead bodies as they would burn up well before arriving at the 'end' of the pit.

Answer 19

This pitfall mechanism seems to be good, sorry for my poor drawing skills, but basicially it would be "water wheel" trap. If a person stands in front of it it would drop them, leading to their death.

Now, depending on the weight of the "wheel" and length of the platform, if someone would run forward and hit the wall with enough force it would be possible to pass this trap. (It's good to have a trap that's possible to overcome if someone knows details behind it.)

Answer 20

This will only work on a cloudless, sun intensive world (maybe a desert environment). Might give you some other ideas so here it goes.

Build a long corridor with collapsed hinged floors. Rig a way for light from the sun to close the floors up so people can walk through them, but near the middle or end of the corridor before a closed and locked door, a pressure plate or a sensor, however you wish to rig it, will trigger some mechanics to align mirrors and concentrate the sun rays into that long corridor. Effectively burning anyone in it.

You'd have to make sure the concentration is high enough to actually burn people in seconds, as well as make sure the mechanism specially the mirrors are well protected so thieves or archaeologists can't just break them.

During the night, the floors drop so nobody can go near and its a long and wide enough corridor that its very hard to spider climb the walls.

Still there may be ways to circumvent the trap such as putting up artificial lights at night or slowly building a makeshift floor at night.

Answer 21

Reasonably modern tech to know to do it, but probably could be done at a much lower level if they knew what to do:

Some low-lying parts of the tomb are swampy. What they don't realize is that under that water there is a layer of dimethyl mercury in dimethyl sulfoxide, aka liquid death. One drop on your skin (or even on latex gloves!) and you're going to die, although a dose that low takes months to kill.

I'm not sure how long it will persist, though.

Answer 22

We need a self resetting stone mechanism, do we?

Well, let's try this:

A door, designed to rise from the floor is arrested in place by a ground plate that - under weight on the far end - tilts to release the door. To lift the door, it is resting on a lever, granite reinforced with copper. On the far end of the lever, a weight is mounted that in itself is enough to lower itself and raise the door, but NOT in combination with the weight of the latch. So once the trap is triggered, the door closes.

Now, the reset mechanism: our counterweight sits in a basin, that under some circumstances (like once a lunar month) is flooded by a natural water source. Since the water changes the bouyancy from nothing to existing, a well designed counterweight under water will have too little of a force to keep the door up, thus slowly lowering it back to the ground. At the lowest point the floor plate will again slip into place and keep the door there, until the next person tries to get in.

If the water source dries up the door will remain eternally locked.

Answer 23

Vacuum (powered by Air Pumps)

Discovered by Otto van Guericke, I guarantee that a Vacuum will last trillions of years! Just ask that black thing 330000 feet up in the air!

Just attach an Air Pump to the door, so when it opens and closes, the Air Pump turns on. Your little adventurers will die before they can escape!

Warning: Not foolproof against Bombs/Grenades/Anything that can destroy structures

Answer 24

Design with biology in mind: To echo a few other suggestions you could make trap supportive of a particular type of poisonous creature and even seed the surrounding environment with a healthy population of them. A great example is actually the snake pit in Raiders of the Lost Ark. By creating a big open cool underground place in a region where that is difficult to come by, makes it a perfect spawning/hibernation area for regional snakes. Also you could use bacteria. Bacterial mats can keep virulent bacteria happy for a long time, and if you happen to get a strain that creates its own spores it could potentially survive thousands of years. Viral agents also have an indefinite lifespan, if they are properly preserved (like under vacuum or really dry or cold air). Or just mix them into the dust on the floor before you seal it up.

Grain Trap: (inspired by Aryan's quicksand suggestion) This trap would need a mechanism but it could be very very simple. People will very quickly drown in grain that is in motion. And grain in an arid environment can last for very long time. Basically you could have a mechanism connected to a trapdoor under the grain room, so when it gets tripped the grain begins spilling into a lower basement. Probably not the most reliable trap. But if you get the geometry of the room right it could be effective.

Flooded Vault: By making your entire vault underwater it gives you more options for preserving the workings, while presenting a formidable barrier. The water could be very alkaline (or very acidic). If you can keep the water still, and mostly deoxygenated then very little will grow in it. You could line the walls, floors, and ceiling then with sharp glass or metal spikes. The water might limit your options, but one shot deadfall traps would work great!

Finally I wanted to point out a couple of things to consider (not really traps in their own right). First is a water pressure activation: If you can seal your vault air tight, then you can use water pressure as an activator in the same way as manometer or a moon pool. If someone breaks the seal of your vault, water rushes up into a channel (or room) to equalize the pressure. The second thing is that if you can simply seal up your vault it will protect the mechanisms in it for a very long time. I had the pleasure once of touring a decommissioned experimental reactor prior to its final dismantling. The building on the outside had been falling apart for over 40 years of disuse, but when they unsealed the containment vessel everything inside was still in good condition.

Answer 25

A simple mechanism that is useful if you have access to a stream is a syphon. There is a basin that slowly fills over time until a ceartain level is reached, then it quickly drains all the water from the basin into whatever trap it is connected to and floods/flushes (similar to a toilet). A nice property is that no moving parts are needed and if done right can be self cleaning. Biggest problems are the intake stream or the drain clogging.

Some clarifications:

a stream does not have to be a river, any source of water will do if there is a lake this works too. if the water comes from the bottom the temperature will be almost constant.

not much can be done against erosion except making the trap resistant against it, either by using hard materials or allowing for some damage.

In an alternative trap the basin itself can be a trap by sucking people down with the water. Another mechanism would be needed to make the water rise just enough when people enter.