This former mining valley near Trevaunance Cove is locally known as Blue Hills, a reference to the vivid blue heather that grows here in summer. There's a small sandy beach at the bottom of the valley, lots of rock pools to explore, and the offshore stacks offer great snorkelling. It's a mile east of St Agnes, off the B3285 (signed to Wheal Kitty). Road access is steep and parking limited; better to park at the top and walk down.
The valley is littered with mine workings and chimneys, one of which is home to Cornwall's last remaining tin workshop, Blue Hills Tin Stream.
North of the beach, the coast path leads up to Perranporth Airfield, built during WWII but now used by local flying clubs. Along the way, you'll be rewarded with spectacular views back towards St Agnes.