Holy Island (LIndisfarne) was always one of those places I wanted to visit.
For me this was a bit of a historic and cultural pilgrimage. Lindisfarne Abbey was founded by the Celtic monk Saint Aidan, who had been sent from Iona off the west coast of Scotland to Northumbria at the request of King Oswald ca. AD 635 and became the base for Christian evangelising in the North of England. It has a fantastic sense of place and antiquity
You drive to Holy Island along a famous causeway. If you get the tides wrong....goodbye car. There's a little refuge in the middle where you can clamber up and watch your car float away
But that adds to the sense of isolation, as well being so obviously why it was selected as a citadel