Lindisfarne, the Holy Island, is isolated from the mainland by the tides for five hours a day, but can be visited during low tide. Most visitors flock to the 16 century castle, which is normally quite picturesque, but is now shrouded in scaffolding as part of its restoration. I found the hike to the castle quite beautiful, along the border of this sheep farm.
Saints Aidan and Cuthbert, both living in the first century, spent time on this island. Saint Aiden was an Irish missionary who founded a monastery here, and St. Cuthbert was a monk who lived as a hermit on Inner Farne and later became bishop of Lindisfarne. (Source: Eyewitness Travel, Great Britain.)