The causeway to Inch Island. I did a little 8km loop using a little of the disused railway line on the shore and then over the road bridge to the island and around to this causeway. Not sure why this was constructed when there already is a bridge nearby or perhaps a new wider bridge replaced this for motor vehicles.
And another raised causeway, not crossable nowadays but it carried the railway c1850. - 1953. I wish they'd develop this into a proper cycle route.