Most people who have travelled to/from Islay via Port Askaig will at some point have noticed the ruins on Am Fraoch Eilean on the Jura side at the southern end of the Sound of Islay. This is Claig Castle, once a quite important castle on the west coast of Scotland. Someone from Cine Gate has flown a drone over it for a closer look:
It is probably around 500 years old, dating back to medieval times, and once was a Macdonald stronghold. Certainly an excellent position to control the area and any traffic passing through the Sound of Islay!