The first lighthouse at Fornæs went up in 1839 to drawings by Georg Holgreen, built in the old manner with the tower integrated directly into the keeper's house — light and household as one structure, so that the man responsible never had far to go. It was fitted with rotating mirrors. Fifty-three years later, in 1892, the present tower replaced it: granite, plain, and considerably more serious about the weather. The keeper's house survived alongside. That pairing — nineteenth-century domestic brickwork attached to a stump of quarried stone — is still what a visitor finds at the end of the road.

The engineering deserves a closer look than most lighthouses get, because the specification is unusually well recorded. The tower rests on a concrete foundation three metres deep and 8.8 metres across, poured onto solid limestone bedrock — the same Danian chalk that stands up as cliffs a few kilometres north at Sangstrup. Above that sits a half-metre granite base, and above that twenty-two metres of granite tower, carrying the light thirty-two metres above the sea. Inside, eighty-four granite steps spiral upward, each one built with a single end mortised into the outer wall so that the stair is cantilevered from the tower itself rather than resting on any inner column. The woodwork is teak. The lantern room at the top is a cylinder 3.7 metres in diameter, its glazing 2.8 metres high and divided by twelve iron bars. Nothing about it is decorative. Every dimension is an answer to wind.

The light kept modernising underneath the same stonework. An acetylene lamp arrived in 1902. In 1924 the station was electrified using British lighthouse technology, and the era of tending flames ended. Then, in 1976 and 1977, something larger was built next door: a 365-square-metre, two-storey control centre from which a whole network of automated Danish lighthouses could be run remotely. For a couple of decades, this windswept cape was a nerve centre. On 1 January 2000 the control centre closed and its functions moved to Copenhagen, and Fornæs went from supervising other lighthouses to being supervised itself, from an office on the other side of the country. There is a particular kind of quiet that settles on a place after its job is transferred to a capital city.

A headland that far out draws things toward it. Fornæs is a significant staging point for migrating birds, funnelled along the coast and out to the tip, and the ground behind the tower is protected — an 85-hectare stretch of beach and coastal field at Stensmark Strand was placed under conservation in 1969, running roughly ten kilometres north and south of the light. Offshore, the limestone continues as stone and chalk reef, which is why anglers and divers turn up in numbers on the gravel car park. There is public access from the parking area onto the beach and the coastal fields either side. And since 2011 the keeper's house has been let as a holiday rental, so it is now possible to sleep in the building whose entire purpose was to keep somebody awake.