Callanish stones. This neolithic stone circle is on the Isle of Lewis in the Outer Hebrides. This is just a segment of the circle of 13 stones. Over the eons, the stones were covered in peat and discovered when a farmer wanted a stone for his wall and saw one stone jutting out of the peat. As he dug, others emerged. The stones form a cross pattern and are thought to have been used for an astonomical calendar associated with the moon.