HA Ha at Chirk Castle

A ha-ha, also known as a sunk fence, blind fence, ditch and fence, deer wall, or foss, is a recessed landscape design element that creates a vertical barrier (particularly on one side) while preserving an uninterrupted view of the landscape beyond from the other side. The name comes from viewers' surprise when seeing the construction. Many landowners used a ha ha in order to get an un-interrupted view of thier land.