A place tainted by order rather than chaos.
A medieval fantasy land, a high European fairy-tale. A valley up in the mountains, big enough for a forest, a lake, a city, and a very small desert. Several days ride across, well protected by mountains, and an army.
Something happened here long ago. The mines in the valley mine clockwork, deposited in great veins that strain against each other, or lie dormant. The metal is unknown, and does not corrode or melt. Immense physical damage will cause a piece to break into two smaller intact pieces.