Buy a few books about permaculture ; watch the videos made by the handful of most reknown guys in the field of permaculture design. Follow a course to ensure understanding the fundamentals.

That's a prerequisite in order to buy some large enough piece of land meeting the criteria for a sustainable place. Better yet: pay a permaculture designer to assess the potential of a property you're interested into buying.

Don't rush into buying because once bought, you'll have to do with the cards that precise property provides. Not all land are equally sustainable. The lesser the potential, the more work, energy and investments will be necessary in the long term.

Let it then evolve by itself without any intervention. Rather than acting, just observe and learn how that precise ecosystem evolves by itself.

Spend week-ends and vacations there, learning the Nature from observation and books.

You don't even need to learn permaculture yourself and even go there regularly, as long as you make sure that the Nature is not blocked in its natural permanent evolution.

Why is it the best investment possible?

1/ you contribute to the protection of the environment in protecting that piece of land.

2/ the biodiversity will augment by itself if no humans intervene.

3/ your kids will be incredibly thankful if they inherit a preserved rural place where they can choose to live (or take refuge in...).

4/ yourself may have to move there of things go bad. Or if you fall in love with the place. Or decide to spend 6 months there and winters in the city so you get the better of both places.

I'm not a survivalist nor do I believe in a collapse of our civilization. I believe in Science and the scientists tell us that things are gonna get bad, since we collectively keep on emitting methane and CO2 and keep on polluting.

10 acres of land is plenty enough. More is better, since pollution sources are further away and the land can offer different opportunities for crops, forests, hunting just to regulate when necessary.

The future is uncertain, so investing in the long term on the financial markets is uncertain too. But some land with a decent natural potential that you let naturally evolve is a no-risk investment: its fertility will keep growing ; its value therefore too and more so that the rest of the land on Earth keep on being over-polluted and the soils depleted of its natural fertility by pesticides.

Invest in Nature for us all, for the Earth, for life and for your children and grandchildren.

You don't need to change your way of life and go live there. It's an investment. Once the right property bought, just doing nothing is good. Just have it checked regularly by someone capable and trustful. You don't want vandals cutting down your trees or hunting (but some hunting may be necessary, though).

So little work and a remarkable yield if you, your children and grandchildren need or decide to live in a preserved and fertile nature. If not, preserved nature will be more and more researched therefore valuable. See the billionaires all buying very large chunk of land in New Zealand. They know what they are doing.

But we know too but most of us prefer betting on Bitcoin rather that on Nature.

Buying a piece of land is like buying a chunk of the bank in a casino. You're certain to win and everybody will applaud your wisdom.