The Pilgrims' Route
Seen from the island looking back towards the mainland, this line of posts marks the safe route to walk across the sands to Holy Island. If you leave it too late to cross over, you can be overcome by the tide, which comes in remarkably quickly, and is very high. The picture in the comments below shows a small wooden refuge that people can climb into for safety.
We'd had a night of very heavy rain, and this was taken fairly early the next morning, when it was still quite misty. Normally, you would be able to see the mainland from here, with extensive views as far as the Cheviot hills 20 miles away.
Taken on our recent holidy to Northumberland, England.