On our recent trip we visited Rodley near Leeds and we went for a walk to explore the local environment. We came across an interesting plaque beneath a modern bridge - you wouldn't notice it if you were boating. It was modest in size and made of cast metal. The plaque contained a poem and links to a blogsite and a mobile phone. The blog was started by the Bridge Repair Man in 2007 and doesn't appear to be active at the moment. It appears that originally it was written in chalk and was much larger.
The plaque was also noted by Alex of the Exploring Leeds web site who thought sections were thought provoking. I agree.
A click on the image below should make it readable. You can also see more details on the Bridge Repair Man blogsite.