Known as a broch, the exact purpose of these iconic iron age ruins is still unknown. however, a group of experimental archaeologists believe that an ambitious project to build a broch from scratch could finally help us to better understand their past. a broch is a huge iron age structure made completely of dry stone with walls five metres thick. we don t have a name for the tribes of people that lived here, and that s perhaps part of the mystery of what a broch was used for. the current academic thinking is that they were houses, houses with five metres thick walls and 13 metres high. still, after hundreds of years of archaeology, we re not entirely sure we have a modern perception of what buildings are. the most complete broch ....