Chûn Castle is a large Iron Age hillfort (ringfort) near Penzance in Cornwall. The fort was built about 2,500 years ago, and fell into disuse until the early centuries AD when it was possibly re-occupied to protect the nearby tin mines. It stands beside a prehistoric trackway that was formerly known as the Old St Ives Road and the Tinners’ Way.
The fort was excavated in 1895, 1925, 1927 and 1930. Much pottery was uncovered; the earliest was dated to the 4th century BC due to its similarity to known Breton pottery of that age. But the fort may have been built upon a much older structure. Chûn Quoit, around 800 feet to the west, is dated to around 2400 BC. It is believed that the fort fell into disuse around the first century AD but was reoccupied and modified several centuries later, until the 6th century. However, occupation may also date to the later Roman period.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.