This demands a full chemical industry developed. (Let's guess they can get at iron ore and coal somehow, and suitable material to make ovens, and you swiped a few axes, saws and shovels to start with. I cannot guess how long it might take to bootstrap those.)
Factories they need to build in chronological order.
bricks, cement & construction supplies
The demigod baby shares the blood supply with the mother, during this time, she also shares the divinity, the strength, and the partial invulnerability. Think "Mirror syndrome" but in a positive way. Instead of a shared illness, it's a shared invulnerability.
Gems such as diamonds, corundums (ruby and sapphire) come from igneous sources. It's possible that one could have a diamondiferous kimberlite blast through a gold or silver ore-bearing formation, or an intrusive dyke that produces rubies or sapphires to penetrate into a similar formation. It's unlikely, given the relative rarity of the two different ...
The creatures eat rocks. The excreta from this is fertile loam that is ideally suited to farming.
They can be trained to eat from rock formations in such a way as to create walls and fortification.
If they eat a metal ore, the metal part is not digested and can easily be separated from the loam to produce pure gold/silver/iron etc.
A problem is of course ...
witchcraft in this world is practiced openly by witches is exclusively female
Mana is continuously produced by the body in order to keep a person alive and functional.
Males can't use magic therefore they can't spend the mana their bodies produce. This results in more mana stored in the organs that can be transferred to the witch.
Females are ...
One way I can think of: Just look at Fukushima and how hard it is to filter radioactive elements out of water - I bet filtering them out of oil would not be any easier. Rather the opposite, I'd expect.
So the ecoterrorists could inject radioactive materials (maybe they stole used up fuel from a nuclear plant and ground it up?) into the oil field, arguing ...
What is the closest I can realistically have my spring to the ocean?
When, as a kid, I went to the sea during summer, it was common knowledge that, in some places along the coast, there were springs pouring fresh water directly into the sea.
One could tell it by both the sudden drop in temperature, especially with calm waters preventing mixing (...
We have a historical precedent for a world with monsters the size of houses.
The difference was arguably higher carbon dioxide, and tropical temperatures, leading to richer and more vibrant plant life. I'm not sure how much it contributed, but the age of the dinosaurs was also largely before plants were mostly composed of cellulose, which is extremely hard ...
Such a city has been already built in reality, and it was even the capital of an empire: Venice
The buildings of Venice are constructed on closely spaced wooden piles. Most of these piles are still intact after centuries of submersion. The foundations rest on plates of Istrian limestone placed on top of the piles, and buildings of brick or stone sit above ...
It's insanely expensive to produce artificially, with estimates of up to $62.5 trillion per gram of antihydrogen. Naturally occurring antimatter in any decent quantity would be beyond lucrative - it would also provide whoever controlled it with a nearly unbeatable energy and weapon edge.
However, it couldn't be laced into the geology of the ...
Throughout history and before the wide use of wood pulp in paper people have used many different types of materials for writing. This varies from
parchment / vellum (made from animal skins, including human!)
papyrus (made from mashed reeds)
People have historically used which ever material filled the ...
Usually such creatures are at least partly based in magic and therefore don't need the usual degree of physical sustenance that would be expected. If you want to ignore this and go for purely biological solutions I suggest referencing Australia's saltwater crocodile which can and will lay up for months hibernating between meals; your dragons don't need to ...
The thing is the massive amount of energy. Sure you could go back and collect iron, coal, oil, etc but is it worth the expense?
Raw materials can be collected from space by asteroid harvesting and the energy to rip a hole in the fabric of time/space just to mine I suspect will be far greater than asteroid mining.
Now where you make your money is collecting ...
Do not make a problem where you do not have one
Demi-gods have been born by fully human mothers in hundreds of myths all around the world for thousands of years without anyone ever making an issue out of it, so you do not need to make an issue of it now.
In fact if you do make an issue of, you are more likely to hurt your work than help it. This is ...
You've hit on the major drawback with solar (or wind) power today: availability factor. It's difficult to predict when these will be unavailable, so you need a backup strategy. Currently, energy sources like this are supplemented in a few ways:
During peak loads or times when the sun/wind is unavailable, many utilities bring online ...
A Victorian wrought iron gate.
..is a highly refined iron with a small amount of slag forged out into
fibres. The chemical analysis of the metal shows as much as 99 percent
of iron. The slag characteristic of wrought iron is useful in black
smithing operations and ...
That's what the Romans did. They dug a pit/trench all the way around the camp, leaving 'gated' areas at the ends to get in and out. when they dug the trench they threw the dirt into a pile on the inside, making a trench down and then a hill back up which the attackers would have to travel. Giving them the high ground and making it easier to defend. On ...
I imagine that the cheapest and most likely option would the use of phase-selective organogelators which are already used to clean up oil spills in some cases.
They're cheap, being based on sugars and alcohols, available in large enough quantities, aren't tightly controlled, make it much more difficult to pump up the oil in the first place, and are ...
My first thought, probably triggered by "spore", is to make them the vents of underground possibly burrowing fungal life forms. Something like the puffball mushroom family but giant sized.
They could periodically vent to spread their spores.
If these spores had a useful property (my first thought is hallucinogenic drug) then they could easily be used as a ...
Fish and whale oils
They have been commonly used by many cultures across history for many purposes. If your people live on an island, I would be inclined to think that they would have access to fish as a food source.
Sources of fuel for oil lamps ... Also widely used were animal fats
(butter, fish oil, shark ...
Alien Life (and their byproducts)
You can't really mine it, but the presence of alien life would be an incredibly compelling reason to send people to Tau Ceti. It's likely evolved in completely different ways than life on Earth has.
Considering that Earth-life has created many substances that we can't reproduce in a lab, it's entirely feasible that Tau ...
Fallen tree limbs, dry leaves, pine cones, twigs -- "woody debris" in general. If they aren't managing their forests, they're going to be full of debris which will just pile up and make the place susceptible to forest fire. So perhaps it's part of their cult devotion that they gather the dead material up in order to tend to the living trees.
You could ...
Same as for normal living beings.
Natural selection: only demigods who manage to not kill their mother in their fetal stage get the chance to be born and pass their genes to their descendants.
All others are simply subject to Darwinian selection.
If you want to sprinkle some divine intervention in the picture, than the deity who impregnated the woman ...
Limit the availability of raw materials, in particular fossil fuels and iron. Without fossil fuels you are limited to wood burning as a power source which is far less energy dense and a much more finite supply. Without iron it's much harder to make much of the earlier engineering feats.
This means you don't get useful steam engines or railways which were ...
You can make stuff from salt. The fine people who worked the Wieliczka Salt Mine did their darnedest to make statutes! From those works, you can see that salt looks a lot like other rocks you find around. You may not even notice until you (or something else) licks it!
Salt itself isn't that hard. The US Department of the Interior has a free .pdf you can ...
Settlers of the North American Great Plains had a similar quandary. Open grassland isn't exactly known for a plethora of quarries or forests. To deal with this, they constructed houses out of sod by cutting and stacking sections of the local turf. However, such constructions were hard to maintain, especially during rain.
Further back, countless cultures ...
There are a couple ways you could handwave this away.
The most obvious is the simple "Magic". How does food production keep up? Druids. How do we keep making swords? Transfiguration. Whenever you are met with some kind of deficiency get a corresponding magic form. This makes pretty much every resource entirely magic produced.
Another good magic one is to ...
In roughly descending order for a non-hunter/gatherer culture (remembering that 'medieval' doesn't just mean 'northern European':
Shelter/survivable temperature/resources for clothes
Salt/food preservative/preservative spices (good foraging might go here too)
Suitable domesticated animals
Wood/mudbricks/wattle and daub/other simple ...
"Space," it says, "is big. Really big. You just won't believe how
vastly, hugely, mindbogglingly big it is. I mean, you may think it's a
long way down the road to the chemist's, but that's just peanuts to
-- A quote from The Hitchhiker's Guide to the Galaxy, Douglas Adams
Honestly, there's not much the natural world could offer that ...
If length of time isn't a factor, you could always go back to before humanity evolved. I'm aware this is basically the plot of Terra Nova, but it means that you don't have to deal with any real resistance.
Homo Sapiens only evolved as a separate species in the last 300,000 years or so, and would only present serious resistance to a modern military ...