This sandcastle may not be sustainable, even though it is build on rocks but while walking about on the beaches on our holiday in south west Scotland was mostly a clean experience, one day the sea brought in some mucky looking foam.
I could see a long patch of water just out from the shore and found myself taking photos of the froth and foam and bubbles as it reached the beach. Other unpleasant things were left behind too, such as dead gulls and what I think may have been a seal carcass. Unfortunately, more colourful things were left behind by people.
The red shoes and sandcastle tools may not have been left deliberately but unless someone claims them, they would not be left long by the tide and will end up as more plastic in the ocean which in turn will probably mean more carcasses on a beach somewhere 🙁