The Yunka cultural sphere can be divided into a north and south cluster of fiefdoms surrounding the northern four rivers, (Esp. de la leche, Lambayeque, Sana, and Jequetepeque. Much. ?,?,?,?) which empty out into the sea. While the coast of the Yunka lands consists of the driest desert on earth, effective dry-farming and canal channeling along the rivers has made the settled territory lush and green. While initially the populace inhabiting the coast sustained the earliest settlements and even cities on a subsistence primarily based on fishing and maritime subsistence, larger populations are now supported by a bountiful agricultural system which produces staples such as corn, potatoes, squash, and cotton. The increasing economic dependence of settlements and territories on the rivers has made them easy prey for conquest and control by the ever warring nobility, and many battles are fought at the borders over the control of the waterways.