We should have the ability to develop our own resources after a while. Plant our own wheat, breed our own cattle and horses, grown grapes and produce wine, cultivate silkworm, breed animals for furs, make incense from natural aromatic substances, grow peppers and stuff for spices, etc. These abilities could be acquired after researching a tech that allows creating a certain resource. Climate and terrain type would influence this ability. You would also have to get permission or instructions from one of the owners of such resources. This could be expensive and nearly impossible to get, like trying to buy a city. P.S. Moderator, please email me if you're gonna merge this thread.