What would be the state of decay in an abandoned city?

Question

I'm writing a novel which takes place in a Middle-ages-type world with magic. The heroes come across an abandoned city in the middle of a deciduous forest. The climate is temperate with rare snowfall and high humidity but not tropical.

The city was built of quarried stone, probably something like granite. Buildings are 1 to 3 stories high. The windows are without glass. The city size was about 5 to 10 thousand people. 1500 years ago, demons attacked the city, killing everyone and had the earth suck up the entire city. The buildings were damaged in this cataclysmic event but some of them are still intact a the semi-damaged buildings shored up certain areas resulting in pockets of underground city. There are some outlets to the forest above but not many.

Assuming there is no flooding, the city is protected from light, there is limited freezing/thawing and plant growth is restricted to fungus and other underground plants. What would the state of decay be inside buildings? Would bed frames, desks, chairs, swords, be gone? weakened? recognizable? Would everything just be a mold and fungus?

Answer 1

If you're looking for longevity the arctic or a desert are obviously the way to go.

That said there are many old buildings that still exist in temperate and tropical climates. Here is a list of really old buildings.

As you can see, the majority show up in the desert, moisture and temperature change are bad for preservation.

There are examples from the rest of the world as well though.

If you are looking to have a relatively intact series of ruins that is perfectly plausible even in your forest.

As an example I would point to the Chichen Itza. The complex/city has existed for about the amount of time you are looking at and is in perhaps the only environment worse for preservation than a deciduous forest...that being a tropical rain forest.

When it was found there were trees literally growing out of the tops of some of the stone structures.

That being said many stone buildings were still intact, and archeologists found Textiles, Basketry, Stone, Bone, Shell, Ceramics, Wood, Copal, Rubber, other Organic Materials, and Mammalian Remains.

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What you are likely going to end up with depends on what you start with. In the case of a fairly advanced society you likely end up with.

• A few major stone structures that are still standing, though it may just be walls or parts of walls
• All wooden buildings and wooden parts of buildings (unless rapidly buried for some reason) will be gone.
• Underground rooms/tombs/cellars etc could well be in decent shape
• Buried items may survive but it is partly luck, where it specifically falls and what the exact environment is like will dictate what remains after 1500 years.

So you have a few stone buildings, mostly ruins, some underground rooms in decent shape and the chance for certain artifacts to survive.

And welcome to the site.

Answer 2

This depends on the city, but absolutely nothing visible would be a reasonable option.

In the case of a major city, scattered blocks of dressed stone. Not a lot else.

Pretty much everything in that time period was made of natural materials, after 1500 years it would be gone. Some larger metal objects might leave traces, say an anvil might appear as a rusted lump of metal. Dressed stone would be weathered but might be recognisable as having once been part of a building but there's a high chance that it would all be buried under a couple of feet at least of soil. Deciduous forest is probably the worst place for this as it lays down new soil fairly quickly. 1500 years is also enough generations of trees to have demolished the buildings.

Answer 3

Stone structures will remain, especially big ones.

Even in the middle of jungles, stone structures can easily survive 1500 years of decay. For reference, the Mayan classical period was around 1500 years ago. In the present day, a Mayan temple looks something like this:

That's the ruins of a temple in the Mayan city of Tikal, which has been abandoned for over a thousand years.

Of course, Mayan ruins have seen some cleaning and restoration in recent years. In an abandoned city, there's likely to be significantly more dirt and vegetation covering old buildings. Smaller buildings are likely to be completely buried and overgrown with trees and plants, while for larger structures, only the top will protrude from a mount of accumulated earth. Basements and lower floors, if open to the environment, will be filled with dirt. Plants and trees will grow on everything, though the degree to which they do so will depend on the sort of environment that the city is in. High rainfall deciduous forests will grow much faster and more aggressively than those in drier climates.

Most other artifacts will break down if exposed to the environment.

Wood and other organic materials will rot and break down first, followed by almost anything metal. Even large metal structures, if exposed to moisture, will rust and break apart well before 1500 years pass.

Of course, that's only true for metals that will rust. Gold artifacts, for example, do not rust quickly, nor do those made of any other noble metals, like silver or platinum. Stone artifacts and statues, if made of sufficiently hard stone and protected from the weather to some degree, are also likely to survive.

Answer 4

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The former is Chernobyl. In 1986, the city was the centre of the worst civil nuclear disaster in human history. Today, it lies abandoned, the stronghold of cockroaches.

The latter is Chichen Itza, Mexico. It was built between 750 and 900 AD by the Itza people, and lay abandoned for a millenium before it was designated a World Heritage site in 1988. It's had minimal restorative work done to it - the major work done there is clearance of the surrounding site, rather than restoration of the pyramid itself.

Which of those two sites has held up better? I'd say it's the latter. Conveniently, that's also the closest parallel to your medieval city. It's also in a tropical climate (hotter and worse for preservation of buildings than you specified). If it can hold out a millenium, that gives you a fair idea of how a medieval city could last, if it was built well.

Answer 5

So, basically everything goes into two categories, organic and inorganic materials.

Everything organic will be gone. No wood, wool, cotton, hemp, silk or anything like that. Major wood items might leave a mound of dirt or similar, but essentially if it's organic something would eat it. Cloth items by bugs and wood by bugs and plants.

Inorganic items are trickier. Stone would likely be diminished, but not gone. General shapes of big things, and totally missing small things. For example, an old stone inn might become a large pile of stones that just happen to have a "wrong" feeling because there is too much pattern to them. Stone fences and smaller stone works would likely be a "lump" in the ground or totally missing (berried under plants etc.) So parts may still be around creating, again a "pattern" like a row of bushes or trees that appear un-naturally straight. Metal materials, would still be around in many place, but would look more like stones then anything else. For example a metal sword wouldn't have it's hilt, or any of it's embellishments, you would instead find just the blade looking all pock marked and raw.

The last effect would be an uncanny structure to things. trees that are too lined up (cause they were planted that way), or a seeming odd, straight path (where a stone road prevented any deep roots.

Answer 6

There are several factors you must consider.

1. Construction style: Most of the temples shown here are predominately stone with small internal chambers, and their shapes are very resistant to tectonic activity. But a more "modern" type of stone building with larger internal spaces and vertical exterior walls is much more susceptible to earthquakes, leading to collapsed structures that are little more than piles of rubble.

2. Scavenger activity: Many ancient sites exist UNDER newer cities (as their geographic location is still favorable for habitation), or the materials were taken for building elsewhere (since it is often easier to scavenge quarried stone than to quarry it anew).

3. Climate change: Were there major floods or glacial activity in 1500 years? Very few places were static over 1.5 millennia (although this is a common assumption in fantasy worlds). A flood can bury a city under mud, wash it away, or leave it underwater as a river now flows through it. An ice age with glacial activity just grinds stone to dust or redeposits them far away. Even dry periods can cause sand storms that can bury cities.

4. Volcanic activity: A lava flow or ash deposit can easily bury a city (i.e. Pompeii). An earthquake can level it, bury it under mud, or redirect a river/lake to cover it in water.

5. Anything organic will degrade unless it is sealed or buried. This is why archeologists usually are excavating refuse pits and graves at sites, those are the places where organic and ferrous stuff (cloth, weapons, seeds, food, etc) might be preserved, or at least leave degraded remains that can be analysed. Things left out in the open have long since been taken or rotted away.

6. Even the type of stone is critical. More porous stone can be easily eroded by rain fall or freezing/thaw cycles as small amounts of water get into cracks, then freeze and expand, enlarging the cracks. So abandoned stone that isn't covered with something (many stone structures used to be coated in plaster or whitewashed, for example) can erode in a wet environment.

There are, in general, very few preserved towns/cities from 1500 years ago that were not either continuously occupied/maintained (and even then, perhaps only a few major structures would have endured like in Rome) or are in any condition to be "explored" outside of excavation. But large stone temple-like structures are probably the best bet (i.e. the central city temple can be explored, while the smaller buildings around it are just foundations covered in vegetation at best) as they were large, probably had the best foundations to resist collapse, and wouldn't be easy to disassemble. In a low humidity environment with minimal vegetation and rain activity, barring sandstorms, earthquakes, floods or volcanic activity, and a remote site that wasn't rebuild or scavenged, it wouldn't be unreasonable to have a large stone pyramid type structure remain in decent condition with explorable interior spaces over that time period.

Answer 7

Seems the climate is similiar to what climate exists in modern countries like italy, there are ruins dated 2 thousand years in italy:

(All images are from Wikipedia)

Pompei Amphitheatre (dated up to 80 BC, so 2000 years):

After 2000 years only most massive buildings are still alive, roofs, high walls are all gone and almost everything is covered by moss.

Monte Consolino ( 1000 years)

While after 1000 years roofs and towers are all gone, you can still see high walls, there are already trees growing inside buildings.

while it is likely most items will be just raided by criminals, it is likely after 1000 years you will still find:

• Pottery (no more paint visibile, unless buried under earth)
• big metal objects will still have their shape (but just appear as a block of rust)
• ropes, tissues, colors all will be gone

Answer 8

Another notable site is Angkor, Cambodia. Many of the structures here, albeit only ~800-900 years old, have been largely abandoned for centuries and unmaintained until only very recently. Another three-quarters of a millenium would probably see them in much worse shape.

As alluded to above, the climate plays a considerable role - freezing climates will see much more severe degradation due to ice damage of stone structures. Dry climates and deserts by far play home to some of the oldest structures on Earth. Wet and jungle climates like Angkor degrade very rapidly with ingress of vegetation and mosses that quickly consume man-made structures.

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Ta Som, Angkor

image credit : By Henry Flower at the English language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8628828

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Preah Khan, Angkor

image credit : By Diego Delso, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=30256645

Answer 9

Your biggest problem is whether any of it is above ground. After 1500 years of fallen leaves, I'd confidently predict that all single-storey buildings and most two-storey buildings will be below ground. For your explorers, the city will just look like a lumpy hill. You might get the tops of the 3-storey buildings if the vegetation is kind, but typically a 3-storey building of that kind of age would have a wooden upper storey, and wooden structures clearly won't survive.