The Mussenden Temple stands on a basalt base at the very edge of the cliff above Downhill Beach, a circular stone rotunda ringed by sixteen engaged Corinthian columns under a copper dome. It was built between 1783 and 1785 as a library, its frieze carved with a line from Lucretius: "Tis pleasant, safely to behold from shore / The troubled sailor, and hear the tempests roar." The building cost £1,169 7s 3½d.
Below it runs the strand: seven miles of sand curving west toward Benone and Magilligan, backed by dunes that shelter waterfalls and birdlife and carry protection as both an Area of Special Scientific Interest and a Special Area of Conservation. You can walk a long stretch of it when the tide allows. There are toilets and disabled parking at the entrance, free parking on the sand where the tides and signs permit, and RNLI lifeguards through July and August. Dogs are welcome outside the summer restriction that runs from the start of June to mid-September.
The village itself is small, set between the strand and the cliff-top demesne. On the road down to the beach, just before the entrance, Temple Cove Coffee Bar looks out to the sea and the temple; it does home-baked cakes, the Victoria sponge in particular. A few steps along, Float-Away offers dry flotation, an infrared sauna and massage, its dry-flotation tank the first of its kind in Ireland.
The Demesne is National Trust land and the main reason to lace up boots. The Bishop's Gate trail is an easy two-mile circuit of about two hours, threading through sheltered gardens and out onto the clifftops, past the apple orchard in the walled garden, the ruined house and the temple; expect gravel, mown grass and some steep steps. The shorter Lion's Gate trail climbs 0.8 miles from the Walled Garden to the clifftop in half an hour, steeper and slippery in places, with dogs kept on leads because there is livestock about all year.
The ruined house behind the temple was Downhill House, built around 1780 for Frederick Hervey, Earl of Bristol and Bishop of Derry at once, and so the Earl-Bishop. He is remembered for a reputed leapfrog race in which local clergy raced along the beach to decide who got the best parish, and for asking that his body be shipped home from Italy packed in a casket of sherry. Fire gutted the house in 1851, after a chimney sweep named Anthony Gallagher fell through a floor and was badly burned; the library was lost, though most of the paintings were carried out. It was rebuilt around 1876, requisitioned by the RAF during the war, then stripped and left open to the sky.
The railway west from Castlerock had to be cut through the headland in two tunnels. Clearing the rock between them in June 1846 took 3,600 pounds of gunpowder in a single detonation known as the Great Blast; five hundred invited guests later sat down to a banquet inside one of the tunnels.
Getting here, the A2 runs a mile west of Castlerock, whose unmanned station is the nearest stop and about half a mile off. The Ulsterbus 134 comes through from Coleraine Monday to Saturday; ask for the crossroads and walk the last few minutes.
In the old graveyard at Dunboe, among walls now thick with ivy, a small obelisk marks James McBlain, the mason who built for the Earl-Bishop.