"A crannóg (Irish pronunciation: [ˈkɾˠan̪ˠoːɡ]) is an artificial island, usually built in lakes, rivers and estuarine waters, and most often used as an island settlement or dwelling place in prehistoric or medieval times" (Wikipedia). Security of access was maintained by hidden stepping stones under the water or by a small boat. This crannóg is in Bonane Heritage Park.