Cashtal yn Ard (The Castle of the Heights) is a Neolithic burial site, dating from around 1800 BC.
It is one of the foremost ancient monuments on the Isle of Man and amongst the largest of its kind in the British Isles.
It was originally a megalithic cairn measuring roughly 130 feet in length and consisting of an open forecourt which led through a portal into five burial chambers.
It would have served as a communal burial place for Neolithic chieftains and their families.
A deed from 1795 gives the site the alternative name of 'Cashtal y mucklagh y vagileragh' (The castle of the field pigsty).
It has been excavated twice, in the 1930s and again in 1999.
Access is from the main coastal road between Laxey and Ramsey and there are excellent views to the surrounding hills and out to sea.