Theoretically, if someone or someones secretly made underground or underwater civilisations or facilities deep below, who do they belong to?

[CarlManvers2019]

Just a thought, let's say a guy manages to found a secret civilisation or secret base in a place or places that with normal technology most people cannot reach

Deep underground or deep below the sea or even up above the very skies

Said civilisations or secret bases harvest their own resources and build their own tech

Let's say that one deep below the Earth and near the Earth's crust harvests all sorts of minerals and makes all sorts of machinery and may have lots of "citizenry" that came from the surface of their own free will and may have essentially voluntarily "disappeared"

If these secret civilisations were discovered, would they belong to countries above/below? Would they all be required to pay taxes in-spite of having infrastructure that has very little to do with the infrastructure

Or say if said secret civilisation was more-or-less independent for centuries or millennia before so many modern governments?

Would Britain have legal ownership over the lands of the Wizards of Harry Potter?

Would North Korea have legal ownership of a hidden flying invisible city of bird people that live in their airspace?

 

[Val the Moofia Boss]

If these secret civilisations were discovered, would they belong to countries above/below? Would they all be required to pay taxes in-spite of having infrastructure that has very little to do with the infrastructure

They only pay if they are forced to pay.

If the modern countries don't have the ability to force the people below to pay tax/tribute, then hidden nations will retain their sovereignty.

For example, take the case of the underground nation. If a civilization was able to build that far down, then they would remain a sovereign nation because today there is nothing we have that could possibly threaten them. We wouldn't be able to collapse their tunnels and you can't "starve them out".

Rule of thumb is that if the nation has the power or the technology to have remained hidden until now - either by existing in an otherwise unsurvivable place (like far beneath the sea or near the earth's crust) or whatever, then they are generally immune to whatever you can throw at them with today's technology and resources, and they have a power advantage of you with their tech and magic.

Also bear in mind deterrence. In Harry Potter, the wizarding world would lose to the muggles if muggle governments tries to fight them, but such a muggle victory would come at such tremendous cost that it is not worth it. Furthermore, the muggles wouldn't really benefit more from wiping out the wizards over keeping their current arrangement, where the wizards keep to themselves and the muggle governments can occasionally request their help with something.

 

[CarlManvers2019]

But would the Muggles or Governments actually on paper legally own those nations? Or be able to call them "Rogue States" or countries that legally cannot exist?

 

[Bear Ribs]

But would the Muggles or Governments actually on paper legally own those nations? Or be able to call them "Rogue States" or countries that legally cannot exist?

On paper is just what it says, whatever the countries involved write down. On paper at first, most likely you'll see multiple claims that might be sorted out in time. This will work much in the same way that, on paper, China owns Taiwan and also the entire South China Sea.

I could see, say, North Korea quite easily writing down that they are the official owners of Subterrania and the Subterranians having a good laugh and ignoring it. On paper doesn't mean anything in this case.

 

[Free-Stater 101]

I chose the impossible...
...

 

[CarlManvers2019]

I could see, say, North Korea quite easily writing down that they are the official owners of Subterrania and the Subterranians having a good laugh and ignoring it. On paper doesn't mean anything in this case.

What about the rest of Za Warudo?

I’m guessing it’d be them that’d decide whether or not Subterrania’s legally part of North Korea or not

 

[Bear Ribs]

What about the rest of Za Warudo?

I’m guessing it’d be them that’d decide whether or not Subterrania’s legally part of North Korea or not

Not really. Every nation's going to write down whatever they like. Za Warudo hasn't managed to keep North Korea from building nukes, they're sure as shooting not going to keep North Korea from writing "We Own Subterrania" on a piece of paper. You might get a UN resolution out of it or even two but those are worth about as much as a pinkie promise.

Ultimately if Subterrania is strong enough that nobody can take them they're their own country, that's how it works. Right now officially whatever is under a country's soil is theirs but if another powerful nation happens to live there, that will change.

If the Subterranians have anything they want to trade they might also attract international trade from the Great Powers who would then have a stronger reason to acknowledge them, though as they aren't quite as prone to grandstanding anyway, the Great Powers are less likely than North Korea to decide they own Subterrania in the first place.

 

[CarlManvers2019]

What if after a sort of sabotage that results in said Formerly Hidden Civilization’s defenses to be destroyed and taken over by another country, would it still legally have been its own country?

Presume that the country that takes over may have accidentally destroyed what made it valuable or able to fight back

Would on paper that be considered an illegal invasion of a foreign nation?

Presume also that they were in talks with other nations who were already or in the midst of acknowledging them

Would it count as an invasion or “liberation” or “reunification”? May also have killed not just the military, but the politicians, businessmen and even the civilians to take over

 

[Bear Ribs]

What if after a sort of sabotage that results in said Formerly Hidden Civilization’s defenses to be destroyed and taken over by another country, would it still legally have been its own country?

Presume that the country that takes over may have accidentally destroyed what made it valuable or able to fight back

Would on paper that be considered an illegal invasion of a foreign nation?

Presume also that they were in talks with other nations who were already or in the midst of acknowledging them

Would it count as an invasion or “liberation” or “reunification”? May also have killed not just the military, but the politicians, businessmen and even the civilians to take over

Talking about "On Paper" is just kind of pointless because every country will justify it however they want when they write it down. I mean Canada will acknowledge that the Native American tribes in their land were once their own nations. China won't even acknowledge that Taiwan is it's own nation right now, much less some hidden Shangri-La they just invaded and took over. Every nation's going to put whatever it wants on paper and they'll all be different.

Edit: Thinking it over, I'd say that nations willing to invade a hidden civilization and conquer it are probably not going to acknowledge that it ever existed as a separate nation in the first place because it being a "rebel province" justifies their invasion. Nations that would acknowledge a hidden civilization as it's own country are less likely to invade it in the first place, unless the US decides to "Nation Build."

 

[Doomsought]

"You and what army" is the first and strongest jurisdictional argument.

 

[ATP]

"You and what army" is the first and strongest jurisdictional argument.

And,to be honest,only one that matter.But - there is another possibility.If those hidden cities are much stronger then we are,then we would be invaded and taken over.
For countries like North Korea it would be better - bird people from flying city could not be worst then communism.