A Broch's an Iron Age drystone hollow-walled structure of a type found only in Scotland. Brochs include some of the most sophisticated examples of drystone architecture ever created, and belong to the classification "complex Atlantic Roundhouse" devised by Scottish archaeologists in the 1980s. Their origin's a matter of some controversy: the theory that they were essentially defensive military structures isn't accepted by many modern archaeologists, and the notion that they were farmhouses's ri… (More on Broch)