Task: Question Answering
Input (English): Passage: Norfolk has a long history of human occupation dating back to the Palaeolithic, and including significant archaeology. Both modern and Neanderthal people were present in the area between 100,000 and 10,000 years ago, before the last glaciation, and humans returned as the ice retreated northwards. The archaeological record is poor until about 20,000 years ago, partly because of the then prevailing very cold conditions, but also because the coastline was much further north than at present. As the ice retreated during the Mesolithic (10,000–5,000 BCE), the sea level rose, filling what is now the North Sea. This brought the Norfolk coastline much closer to its present line, so that many ancient sites are under the sea. Early Mesolithic flint tools with characteristic long blades up to 15 cm (5.9 in) long found on the present-day coast at Titchwell date from a time when it was 60–70 km (37–43 mi) from the sea. Other flint tools have been found dating from the Upper Paleolithic (50,000–10,000 BCE) to the Neolithic (5,000–2,500 BCE).By 11,000 BC, the makers of the long blades had gone. Two timber platforms have been identified within the peat at Titchwell, and may possibly be rare Bronze Age (2,500–800 BCE) survivals. Seahenge is another early Bronze Age site found on the coast at Holme in 1998. It consists of a ring of 55 oak posts and was built in 2049 BC; a similar nearby structure, Holme II, may be almost two centuries older. A large Iron Age fort at Holkham enclosed 2.5 ha (6.1 acres) at the end of a sandy spit in what was then salt marsh, and remained in use until the defeat of the Iceni in 47 AD.Roman period settlements have been discovered all along the Norfolk Coast, notably the complex at Branodunum, which covered at least 23 ha (57 acres) near Brancaster. This site included a fort built on the castrum pattern enclosing 2.6 ha (6.3 acres) within its walls, 2.9 m (10 ft) wide. The fort had internal turrets at the corners and was backed by an earth rampart. Early Saxon sites are scarce close to the Norfolk coast, but a gold bracteate found near Blakeney Chapel was a rare and significant 6th-century find, and there is a somewhat later Saxon cemetery at Thornham. The Danelaw left few tangible traces within the SSSI, but place names such as Holkham ("ship town") reflect the Viking influence. Saxon building foundations were described as the ruins of "Cley Chapel" on a 1797 map, although it is more likely that they belonged to a barn. 
Question: What is the name of the site that consists of a ring of 55 oak posts and was build in 2049 B.C.?
Output (English): Seahenge.