Bryn Celli Ddu

Bryn Celli Ddu is generally recognised as the finest passage tomb in Wales, and unlike many other megalithic sites, it not only has a full entrance passage and a roughly circular chamber, but also lies beneath a mound of earth which was backfilled after the 1929 excavations. It is located on the island of Anglesey.

The oldest remains of the complex are five postholes, which were previously thought to date from the time of the tomb. However, radiocarbon analyses in 2006 revealed that they date from around 4000 BC. This means that the holes date from the end of the Mesolithic period and are therefore around 1000 years older than the next known utilisation phase of the site.

A henge was built around 3000 BC, consisting of a circular rampart and a ditch 21 metres in diameter. Within this circle was an oval stone circle. Burnt human bones were buried at the foot of some of these stones. The serpent pattern stone was found lying nearby, its decoration on both sides suggesting that it was standing upright.

About 1000 years after the henge was built, the site was radically remodelled. All but one of the standing stones were vandalised and the tomb was erected. At 26 metres in diameter, it was much larger than it is now, and will have had a full row of kerbstones. Human bones, both burnt and unburnt, were found in the chamber and in the passage, indicating a number of different burial rituals. In the end, the tomb was sealed by placing a large stone in front of the entrance between the two portal stones.