The remains of a Neolithic chambered tomb. The name comes from the legend of King Arthur. Various legends recount tales of a king, or giant killed by King Arthur buried here. Another claims this to be the burial place of the man himself! A large capstone is supported by nine uprights, and the foundations of a 4.6m long entrance passageway can be seen. To the south is a stone known as the Quoit Stone bearing small man-made cup marks, again legend tells of Arthur's elbows as he prayed, or a giant's as he fell. Signposted from the B4348, 8km east of Hay-on-Wye.