Mysterious structures are dotted throughout the Highlands and Islands of Scotland. Standing proud by the side of roads, with car parks for visitors and information boards, or just a tumble of stones under the bracken somewhere off the beaten path, are the remains of round stone buildings built in the iron age, some of them still several storeys high. These are brochs.

Their exact function, and how they were built still isn’t known. Some of them were investigated, rebuilt, or plundered by the first wave of amateur archaeologists in the 19th Century. Many now make a good picnic spot.

Pete and Matt spoke to Ken and Iain from the Caithness Broch Project to understand more about what these brochs are, and to find out what the difference is between a broch and a cairn.

The Caithness Broch Project is a grass roots charity aiming to promote and preserve existing archaeological sites in Caithness, create an Archaeological Trail around the area, and to build a replica of an Iron Age Broch using authentic building techniques from the time.