(Poll na mBrón in Irish meaning "hole of sorrows") is a portal tomb in the Burren, County Clare, Ireland, dating back to the Neolithic period, probably between 4200 BC to 2900 BC making it older than the Egyptian Pyramids.
The dolmen consists of a twelve-foot, thin, slab-like, tabular capstone supported by two slender portal stones, which lift the capstone 1.8m (6ft) from the ground, creating a chamber in a 9m (30ft) low cairn. The cairn helped stabilize the tomb, and would have been much higher originally. The entrance faces north and is crossed by a low sill stone.
A crack was discovered in the eastern portal stone in 1985. Following the resulting collapse, the dolmen was dismantled, and the cracked stone was replaced. Excavations during this time found that between 16 and 22 adults and 6 children were buried under the monument. Personal items buried with the dead included a polished stone axe, a bone pendant, quartz crystals, weapons and pottery. With its dominating presence on the limestone landscape of the Burren, the tomb was likely a centre for ceremony and ritual until well into the Celtic period.