Although Chûn Castle is only a few hundred yards from the Quoit, it comes from a much later period. Built during the Iron Age, during the third century BC, it is over 2000 years later than the Quoit. Although it is in a ruined state, its size can still be well appreciated. It is 85m (280ft) in diameter, and consists of a central area, surrounded by two concentric granite walls with external ditches. The outer ditch was 6.1m (20ft) wide, and the outer wall now 2.1m (7ft) high, but may originally have been 3.0m (10ft) high. The inner wall (now mostly destroyed) was some 4.6m (15ft) to 6.7m (22ft) thick, and could originally have been some 6.1m (20ft) high. There were originally some Iron Age huts in the inner area, though no trace of these now remain. The site was re-occupied in about the sixth century AD, when 15 or 16 stone houses were built around the inner courtyard, and a furnace for smelting tin was made, just south of the well in the NW quadrant of the inner area. The entrance was also reshaped to make a staggered en- try, which would have made attack difficult. The site was plundered during the 18th century of stone to construct the Madron Workhouse and pave some streets in Penzance.