Stack Rocks, the Green Bridge of Wales and St Govan's Chapel

The southern edge of Pembrokeshire is carboniferous limestone rather than the older rock further north, and it behaves differently: flat on top, vertical at the edge, and full of arches, stacks and blowholes.

Start at Stack Rocks, where two limestone pillars stand just offshore, packed with guillemots from April to July — elegug is the Welsh for guillemot. A hundred metres west is the Green Bridge of Wales, the most photographed sea arch in the country, best seen from the viewing platform. It won't last forever; arches like it collapse, and the neighbouring stacks are what's left of older ones.

Walk east along the clifftop. The going is flat and easy, which is unusual for this coast, and the drama is all in the edge: Huntsman's Leap, a narrow chasm named after a rider who supposedly jumped it and then died of fright looking back; the Cauldron, a collapsed cave; and long stretches of sheer white cliff that draw climbers all summer.

At the far end, a flight of stone steps drops into a cleft in the cliff to St Govan's Chapel — a tiny 13th-century building wedged into the rock, on a site said to have been a hermit's cell since the 6th century. Local legend says you can't count the steps twice and get the same number.

Practicalities. There is nothing at either end: no shop, no toilets, no water. The pubs at Bosherston and Stackpole are the nearest.

If the range is closed, the walk from Bosherston to Broad Haven South and Barafundle is the alternative, and it's open all year.