Helen Mark discovers a wilderness in the heart of Penzance, in West Cornwall. It's a rocky headland loved by local people, with steps into the open water and views of St Michael's Mount. If you set up a time-lapse camera here at Battery Rocks, you'd see a steady stream of people arriving at this unobtrusive place from sunrise to sunset. It's popular with swimmers, snorkellers, rock-poolers and poets, and it's a haven for wildlife. Battery Rocks is a haven for people too, a life-saving place of joy and community, according to snorkelling instructor Katie Maggs. Helen goes snorkelling with Katie and discovers how this place inspired poet Katrina Naomi's new collection 'Battery Rocks'. Lucy Luck takes Helen on a rock pool ramble and Mike Conboye leads her in a sunrise swim at the rocks, with music from his acapella group, Boilerhouse. Producer: Mary Ward-Lowery