Pentewan, on the south coast of Cornwall, was a thriving harbour and commercial port in the early 20th century until the entrance silted up due to the slurry from china clay mining industry in the area. This left the harbour as a a huge and rather attractive village pond.
The last large commercial ship set sail from the harbour in 1940. After that, small fishing boats could still use the harbour right up until the 1960's when the entrance was completely sealed off.
The old lock gates, winching machinery, and mooring posts still remain as a reminder of it's former industrial history, but now only ducks and seagulls sail on these waters.