The Grey Cairns of Camster are two large Neolithic chambered cairns that are among the oldest structures in Scotland, dating to about 5,000 years ago. The cairns demonstrate complex neolithic architecture, with central burial chambers accessed through narrow passages. They were excavated and restored by Historic Environment Scotland in the late 20th century. The cairns were constructed in the third of fourth millennium BC in an empty, boggy and peat-covered moorland. Although the surrounding countryside is now inhospitable with little population, it was a fertile farming land in the Stone Age, only becoming covered in peat during the Bronze Age.