Seahenge

 Seahenge, also known as Holme I, was a prehistoric monument located in the village of Holme-next-the-Sea, in Norfolk. Seahenge was a timber circle with an upturned tree root in the centre. Along with the nearby timber circle Holme II, it was built in the spring and summer of 2049 BCE, during the early Bronze Age in Britain.

The site consisted of an outer ring of fifty-five small split oak trunks roughly forming a circle; their split sides faced inwards and their bark faced outwards, with one exception, which was placed in the opposite position. One of the trunks on the southwest side had a narrow entrance carved into it. In the centre of the ring was a large, inverted oak stump.

In early 1998, John Lorimer, an amateur archaeologist, was catching shrimp with his brother-in-law on Holme Beach when they found a Bronze Age axe head in the silt, but at first did not know what it was. Intrigued he visited the site several times and found the sea had washed away the silt and sand to partially reveal the inverted tree stump. He continued to monitor the area as wave erosion gradually exposed the surrounding ring of wooden posts, confirming that the site was an intentional human construction. Lorimer contacted the Castle Museum in Norwich.

Seahenge was named by the press in 1998 after the more famous prehistoric structure Stonehenge in Wiltshire. There were protests against the excavation by both locals, who wanted it to remain as a tourist site, and Neopagans, who believed that the removal of the structure was an insult to the religious beliefs of its original builders, among other concerns. In an effort to preserve the timber, its remains were taken to an archaeological museum for preservation. In 1999 and again in 2008, a reproduction was put up in place of the original.

Due to controversy about the excavation of Seahenge, Holme II was left in place to be monitored as it is gradually destroyed by erosion. Researchers have been unable to determine the purpose of the site.
One theory of use is that Seahenge was a mortuary enclosure for the use of excarnation rather than a meeting place, though there is no direct evidence for this.

Sources:
Seahenge and 2nd Circle Were Built at the Same Time, Archaeology Magazine

Seahenge is Coming, Norfolk Museums & Archaeology Service

Seahenge: a quest for life and death in Bronze Age Britain, Francis Pryor