Almost all the videos on this channel are fascinating btw. Greenhouses enveloping entire houses/villages[0][1] in northern Europe to earthships[2] to someone growing citrus in Nebraska using trenches[3] to entire villages underground in Australia[4]

[0] https://www.youtube.com/watch?v=irp_HPzfxbQ

[1] https://www.youtube.com/watch?v=EzKSKqjEmDA

[2] https://www.youtube.com/watch?v=wVp5koAOu9M

[3] https://www.youtube.com/watch?v=ZD_3_gsgsnk

[4] https://en.wikipedia.org/wiki/Coober_Pedy

I'd also recommend the channels FLORB and Happen Films though they're admittedly a little corny.

https://www.youtube.com/@happenfilms

https://www.youtube.com/@FloatingOrbProductions

Crime Pays But Botany Doesn't recently did a tour of an interesting alt home as well. https://www.youtube.com/watch?v=2YyWspKzbAw

Sure, 4 Ha (10 acres) is an inconsequential corner of a 4,500 Ha farm with rural zoning - no one's going to care if you carve out a few underground spaces and rock wall them entirely and only at risk to yourself.

Community standards kick in once you open such things to the public or move to sale w/out disclosing an invisible (or plainly visible) potential hazard that the buyer should be aware of.

Well, in rural Australia at least.