what is the history of the idea of land ownership?

what is the most likely reason and timeframe for society to change such that land ownership as it is known today would be unrecognizable?

what areas of land ownership today are ambigious? the air space above the land, the "mineral rights" below the land.

how do countries pay each other when each country has the ability to create new currency (or even easier, the digital representation of currency)? i suppose the threat of inflation in their own country is one reason.