Stand on the cliff edge facing west and you will see them: two cone-shaped daymarks, one painted red and the other striped black and white. They are not decorative. About a kilometre offshore lies the Runnel Stone, a partly submerged reef that has wrecked ships for as long as there have been ships in the western approaches. The Corporation of Trinity House erected the black-and-white inland cone in 1821, with a plaque on its back recording the date. The red seaward cone followed later. The system is elegant: from a vessel at sea, the black-and-white cone must always be kept in sight. If the red cone slides across and obscures the black-and-white one entirely, the vessel is on top of the reef and likely about to die. Hammond Innes used the markers in his 1940 thriller The Trojan Horse, calling them the Cones of Runnel. Ships still navigate by them today.

The squat building on the headland began life around 1905 as a single-storey Coastguard lookout, in service by 1910. A second storey was added later, after a French trawler was wrecked at the foot of Wireless Point at Porthcurno in March 1956 and the watchers concluded they needed more height to see what was happening. The official Coastguard withdrew the station in 1994 as part of a national rationalisation, but the local community refused to leave the coast unwatched. On 21 October 1996 it reopened as NCI Gwennap Head, staffed by trained volunteers of the National Coastwatch Institution. They sit in shifts through the year, looking out for vessels in difficulty, swimmers in trouble, walkers on cliffs too steep for them, and the occasional bird so rare it stops the radio. The Runnel Stone Marine Conservation Zone, declared in January 2016, is measured as a 3.5-kilometre arc from this lookout.

Gwennap Head is one of the great seawatching stations of Britain. Its position at the south-western tip of Cornwall, jutting into the migration corridor for North Atlantic seabirds, brings to its cliffs an annual cast of gannets, Manx shearwaters, fulmars, guillemots, razorbills, shags, and cormorants, sliding past in their thousands. In July and August come the longer-distance travellers: great shearwaters bred on Tristan da Cunha in the South Atlantic, Cory's shearwaters bred on Mediterranean islands and in the Azores, both species drifting north in their summer migrations and rounding Cornwall on the way. From 2007 to 2011 a formal survey called Seawatch SW, led by Dr Russell Wynn, sat volunteers on the cliff edge twelve hours a day from mid-July to mid-October. Most of what they recorded was routine. On 28 August 2015, a red-billed tropicbird, a species that has no business at all in Cornish waters, sailed over the Runnel Stone.

On the north flank of Gwennap Head a small stream drains into the boulder-strewn cove of Porth Loe. On the morning of 15 March 1905 the barque Khyber, sighted from the Wolf Rock the previous night, came ashore on those boulders and broke apart within fifteen minutes. The men still building the nearby coastguard houses ran with ladders and saved three of the crew. Twenty-three others did not survive. They are buried together in St Levan churchyard a few miles inland. The Cornish weather has scrubbed the rocks of any physical sign that the wreck ever happened. Almost everything in this landscape has a story like this attached to it, layered into the granite the way the maritime heath layers across the cliff tops: things that happened, in this exact place, that almost nobody who walks here today knows about.

In 2010, two botanists named Helen and Laurie Oakes were poking around the maritime grassland near the cliff edge when they found perennial centaury, Centaurium scilloides, a small pink flower that had not been seen in Cornwall, or indeed anywhere in England, since 1962. It had survived in only one Welsh location. The rediscovery, after almost fifty years, was credited to the reintroduction of cattle grazing under a Higher Level Stewardship agreement; the cattle were keeping the sward open enough for the centaury to compete again. The grassland here is at its richest in late spring, when spring squill, thrift, sea campion and kidney vetch flower together against the granite, before the purple of the bell heather takes over in midsummer. A clouded yellow or a hummingbird hawk-moth may go past on the warm air. The headland is small, but it is genuinely full.