Bryn Celli Ddu
During the Neolithic period a stone circle and henge stood at the site. There were 14 stones in the circle, and the henge was about 30 m in diameter, with a ditch about 5 m across. The ditch was about 2 m deep. There was probably a path or causeway across the ditch to the henge. A small human bone from the ear, covered with a flat stone, was found in an area of burnt material in the centre. The amount of silt in the ditch showed that it had been used for a long time.