Cashtal yn Ard is the largest Neolithic tomb in the British Isles and one of three on the Island, dating back roughly to, 2000 BC. That said, it can be a bit tricky to find, but does make for a picturesque walk. It is situated in Maughold, close to the Dhoon Quarry, north east of Glenmona and south of Cornaa. There are signposts and if you can find those, you will find, Cashtal yn Ard.
Excavated twice, first in the 1930’s and recently (1999) it measures just over 130 feet and is divided into five chambers built around what was originally a megalithic Cairn or pile of stones.