Head Harbour Lighthouse, also known as East Quoddy Lighthouse.
You can see how well surrounded and inaccessible it is at high tide!
There are several "extreme Danger" signs on the pathway of islands to stress
that you have to know when you MUST leave, or not even attempt to get out to
the lighthouse. The tide comes in fast, and you can end up stranded for 8 hours
if you are not watchful!