The name turns up in a legal case in 1727, which means it was already established by then; locally the hill had also been known simply as Kollen, "the knoll." That gap between the two names is the whole story. One is a description. The other is a claim.

What justifies the claim is not the number but the drop. Most of Denmark's higher points are broad agricultural swells you can drive over without registering the climb — you reach the summit of the country and find a field. Himmelbjerget falls away steeply to Julsø directly below, and that face gives it something the taller hills lack: an edge. Søhøjlandet, the "lake highlands" around it, is the most broken terrain in the country, and this is its viewpoint.

The brick tower on the summit is not decoration. Construction began in 1874 and it was dedicated on 6 June 1875, designed by Ludvig Fenger, who would later become Copenhagen's city architect. It stands twenty-five metres and it was raised to the memory of King Frederik VII — specifically as the Danish people's thanks for the constitution of 1849, the document that ended absolute monarchy and made them citizens rather than subjects.

Read in that light, the tower makes the hill legible. A country that had just given itself a constitution needed somewhere to be a country at, and it chose the highest ground it thought it had. Other monuments cluster near the top, most honouring individuals: Steen Steensen Blicher, A. F. Tscherning, Leopold Budde, Vilhelm Beck. One stone is not for a person at all. It commemorates the extension of the vote to Danish women in 1915.

The gatherings came before the tower. The poet and pastor Steen Steensen Blicher organised the Himmelbjergfest here from 1839 to 1844, national assemblies on a hilltop at a moment when "the Danish people" was still a proposition rather than a settled fact. People came to admire the view and to celebrate the birth of a nation, in the open air rather than in a hall in Copenhagen. In 1854 Michael Drewsen led a constitutional celebration on the same ground.

The habit stuck. For more than two hundred years this hill and the country beneath it have been a place Danes go to mark things collectively — which is a strange function for a hill of 147 metres, and exactly why the demotion of 1847 changed nothing.

The proper approach is from the water. In the nineteenth century steamboats began ferrying visitors to Himmelbjerget from across Julsø and the Silkeborg lakes, and the tradition never lapsed. The historic steamship Hjejlen — "the Golden Plover" — still carries passengers here from Ry and from Silkeborg, arriving at a jetty below the slope so that the walk up is the last stage of a journey rather than a car park and a footpath.

There is a sign at the summit pointing the way "to the boat." It is a small thing and a slightly comic one, but it tells you how the place is meant to work: you come by lake, you climb, you look, you go back down and sail away. Walkers can also reach it overland — the long-distance Aarhus-to-Silkeborg hiking route passes through, and shorter loops thread the woods and heath around the hill itself. However you come, the view from the top runs out over Julsø and the wooded ridges of Søhøjlandet, and the country's real high points, wherever the surveyors put them, are nowhere in sight.