English: Reconstruction of the Iron age building at Navan, Co. Armagh, Ireland. Archaeological excavations have revealed that the construction of the 40 metre mound dates to 95 BC (securely dated by dendrochronology).[3] A roundhouse-like structure consisting of four concentric rings of posts around a central oak trunk was built, its entrance facing west (prehistoric houses invariably face east, towards the sunrise). The floor of the building was covered with stones arranged in radial segments, and the whole edifice was deliberately burnt down before being covered in a mound of earth and turf (there is archaeological evidence for similar repeated building and burning of Tara and Dún Ailinne).[3] The bank and ditch that mark the enclosure were made at the same time.