This drystone walling was important in reducing the erosion of the river banks. It lies within a triple concentric drystone facade and is covered with a corbelled vault. Many stone bee boles are in drystone walls, but others are mortared. A broch () is an Iron Age drystone hollow-walled structure found in Scotland. Lubaantun is a drystone constructed site with ruined pyramids and stone tombs. The tower features two skins of drystone walls, with stone-floored galleries in between. Besides cairns, the Botiala area also features a few other drystone monuments. It was strengthened by drystone walls at the end of the century. As a result, crannogs made completely of stone and supporting drystone architecture are common there. It is in a small wood and surrounded by a circular drystone wall. In the eastern part are the remains of an early drystone oratory. It is the base for a licensed community radio station, Drystone Radio. Drystone walls were built to protect the soil. Drystone retaining walls are normally self-draining. Also notable is the drystone work supporting some of its hairpin bends.