1. Every Supervillain Needs a Secret Base

Three may keep a Secret, if two of them are dead.

-Benjamin Franklin (1735)

Every villain needs a place to live, work, and scheme. While civilians may content themselves with a "home," an "office," or a "home office," you're going to live the supervillain dream by plotting in style and comfort from your own palatial secret base.

There are some restrictions to keep in mind when scoping out locations for a secret base. The "secret" part of "secret base" means it should be hidden, or at the very least inaccessible: you don't want meddling do-gooders easily stumbling across it. "Base" means it should be sustainable and self-sufficient, able to support you (and ideally a staff of henchpeople) for months if not years at a time. Remember, if you can't bunker down in it for the long term, then you don't have a base: you have a vacation home.

And one simply does not take over the world from a secret vacation home.

Background

First, let us dissuade you from what you're already thinking, which is this:

Obviously the best place for me to build a secret supervillain base is inside a volcano, this is easy, I don't even know why I bought this book since I know all this stuff already.

-You (currently)

Building in an active volcano is a bad idea: it can explode with little to no warning, cooking you alive as the air fills with toxic gases and rocks rain from above onto a floor that is literally lava. Even a dormant volcano means you're living inside a very visible, non-secret hole/tourist attraction.

Your main concern here is self-sufficiency: if your base is to support you and your henchpeople without having to rely on the outside world, it will need to be a certain minimum size. The precise nature of that minimum size depends on how you answer the question of "wait, how much space do we really need to keep a human being alive indefinitely?"

Various authorities have attempted to answer this question throughout history. In the 700s CE in England, land was measured in hides, which reflected the amount of land thought necessary to support a family. Hides ranged in size from around 240,000 to 728,000 square meters (m), depending on the productivity of the land, but around the Norman conquest in 1066 CE, they became standardized at around 485,000m: slightly less than half a square kilometer. Whether families at the time included just immediate family members or also extended family is now unclear, but if you assume a small family of just four people, that works out to 121,250m of arable land per person.

Factoring in the modern farming technologies developed over the past millennium, a more recent 1999 calculation determined that a diversified and sustainable European (meat-eating) diet demanded 5,000m of farmland per person, further calculating that if you assumed a largely vegetarian diet; no soil degradation, erosion, or food waste; ample irrigation; and godlike farmers who both planted and tended to their crops perfectly, you could probably get that number down to just 700m a person. Lower numbers are better here: they help keep your base reasonably sized and have the side effect of making it easier for the rest of the world not to starve to death. That's a good thing, given that the United Nations' Food and Agriculture Organization's measurements of global arable land per person have been trending downward for decades: in 1970, it was 3,200m per person; in 2000, it was 2,300m per person; and in 2050, the global arable...