Bryn Celli Ddu Neolithic passage tomb mound entrance on Anglesey

c.3000 BC · Neolithic · Cadw · Summer Solstice Alignment · Anglesey

<span lang="cy">Bryn Celli Ddu</span>

One of the finest Neolithic passage tombs in Wales — a 5,000-year-old corbelled chamber aligned to illuminate the midsummer sunrise, set in the agricultural heartland of Anglesey.

At a glance

A 5,000-year-old Neolithic passage tomb on Anglesey — free open access, chamber you can enter, and a passage aligned so the midsummer solstice sunrise illuminates the burial chamber. One of the finest prehistoric monuments in Wales. Free (Cadw), LL61 6EQ.

About Bryn Celli Ddu

Bryn Celli Ddu — "the mound in the dark grove" — is a Neolithic passage tomb built approximately 5,000 years ago (c.3000 BC) in the agricultural heartland of Anglesey. It is one of the best-preserved prehistoric monuments in Wales and one of the finest examples of a passage tomb in Britain — a corbelled stone chamber reached by a narrow passage, covered by a circular mound of earth and stone.

The monument was built on the site of an even earlier ritual enclosure — a henge comprising a circular ditch, bank and standing stones. The Neolithic builders partially dismantled this older monument to construct their passage tomb, incorporating one of the henge stones into the new structure. The site therefore represents at least two phases of prehistoric ritual use spanning many centuries.

The chamber's passage is aligned with deliberate precision so that at the summer solstice (around 21 June), the rising sun shines along the passage and illuminates the back of the chamber. This astronomical alignment — demanding considerable planning and astronomical knowledge — demonstrates that the monument's function was tied to the solar calendar. Similar solstice alignments are found at Newgrange in Ireland (built c.3200 BC) and, in a different form, at Stonehenge. The comparison gives a sense of the intellectual and organisational capacity of these Neolithic communities.

During excavations in the 1920s and 1930s, archaeologists found a remarkable carved monolith (the "Pattern Stone") within the mound — its abstract spiral and geometric patterns have no parallels elsewhere in Wales. The original is in the National Museum Wales in Cardiff; a replica stands inside the chamber.

Visiting Bryn Celli Ddu

  • The passage and chamber — Enter the low passage (stooping required) and stand inside the corbelled chamber — bring a torch. The replica Pattern Stone is inside.
  • The mound exterior — Walk around the circular mound — observe the ditch and the relationship between the entrance facade and the surrounding landscape.
  • The solstice event — Cadw organises supervised solstice dawn visits every June — book well in advance via cadw.gov.wales.
  • The field walk — The 500-metre path from the car park crosses typical Anglesey farmland — good for a short walk and views to the Menai Strait.

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