Just six miles from the center of Belfast, County Down, on the plateau of Ballynahatty above the River Lagan, is one of Ireland’s great Neolithic henge monuments: the 200 m wide Giant’s Ring. For over a thousand years, this area was the focus of intense funerary ritual seemingly designed to send the dead to their ancestors and secure the land for the living. Scattered through the fields to the north and west of the Ring are flat cemeteries, standing stones, tombs, cists, and ring barrows – ancient monuments that were leveled by the plough when the land was enclosed in the 18th and 19th centuries. A great 90 m long timber enclosure with an elaborate entrance and inner ‘temple’ was first observed through crop marks in aerial photos. Excavation of the site between 1990–1999 revealed a complex structure composed of over 400 postholes, many over 2 m deep. This was a building in the grand style, elegantly designed to control space, views, and access to an inner sanctum containing a platform for exposure of the dead. By 2550 BC, the timber ‘temple’ had been swept away in a massive conflagration and the remains dismantled. Ballynahatty was one of the last great public ceremonial enterprises known to have been constructed by the Neolithic farmers in Northern Ireland, an enterprise proclaiming their enigmatic religion, ancestral rights and territorial aspirations. This report reconstructs the remarkable building complex and explains the sophistication and organization of its construction and use. The report sets the site and excavation in the wider development of the Ballynahatty landscape and its study to the present day.