Walled Cities

A city that's surrounded by tremendous, 60-foot sheer-ish walls of sandy yellow stone. The exterior is all mammoth slabs, laid without mortar. The interior wall is gently stepped, and each steppe is a garden. The look is as if a verdant forest had tumbled down a hillside, with neat rows of crops interspersed. Narrow, defensible paths run throughout the foliage and farmland up to the top of the wall where a broad flat walkway encircles the city. Inside the huge form of the wall are miles of tunnels, many of which are taken up by irrigation pipes and equipment for farming (seed, fertilizer, and tools). The city inside the walls is similarly constructed all of ziggurats and flat-roofed pueblos, all the area possible dedicated to greenery. The orchards and farms here provide the only safe food for miles in the middle of this [desert/jungle/ocean/tundra]. The only water, too, fed by a seemingly infinite spring of clear fresh water under the city's heart.