Knocknarea is a large prominent hill west of Sligo town in Ireland, with a height of 327 metres. On the summit of Knocknarea is a large cairn about 55 metres wide and 10 metres high, making it the largest cairn in Ireland outside Brú na Bóinne in Meath. Although it has not been excavated by archaeologists, it has many features of a classic passage tomb.
The cairn is flat-topped and several kerbstones can be seen on the northern side. It is believed to date to around 3000 BCE, during the Neolithic (New Stone Age). It is known in Irish as Miosgán Meadhbha (Meadhbh's heap), and in English as Maeve's Cairn or Maeve's Tomb. Meadhbh is a queen of Connacht in Irish mythology, who is believed to have originally been a goddess.
The ancient cairn is a protected National Monument. In recent years, archaeologists have warned that it is being eroded by hikers climbing on it and moving or removing stones. The large number of climbers is leaving scars on the cairn and may be destabilizing the tomb inside. Irish folklore holds that it is bad luck to damage or disrespect such tombs and that doing so could bring a curse.
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.