I cycled to a tiny place called Sunderland Point today.
To get there you have to go via a small road through a salt marsh that may or may not be passable, depending on the tide. I like salt marshes.
According to Wikipedia, "Sunderland is unique in the United Kingdom as being the only community to be on the mainland and yet dependent upon tidal access."
It's got a shitty history as being a port that was part of the slave trade. Sadly there's quite a bit of that history around Lancaster.