Polruan Castle

Polruan Castle, also known as the Polruan Blockhouse, is a medieval artillery fortification built around 1380 to protect the mouth of the River Fowey in Cornwall. Constructed following a French raid on Fowey in 1457 during the reign of Edward IV, the blockhouse worked in tandem with Fowey Blockhouse on the opposite riverbank with a heavy chain stretched between them to control harbour access. The walls are 6 feet thick, and the chain was last deployed in 1666, making it one of only five surviving chain towers in England and the oldest of its kind. Protected as a scheduled monument and Grade II* listed building, it is owned by the Polruan Town Trust and remains open to visitors today.