The story runs backwards from what you would expect. In the Stone Age this was a large lake. The lake dried, and Iron Age farmers worked the ground it left behind. Then the climate turned: through the Middle Ages precipitation increased, peat moss spread across the abandoned fields, and the farmland drowned under its own vegetation to become one of the biggest bogs in Europe. Store Vildmose reached its maximum extent in the 1800s, just in time to meet the machinery that would undo it. Peat is a patient archive. As it was cut and dug through the centuries, the bog gave back relics and artefacts from the Iron Age farms it had buried — tools returned by the same wet chemistry that had swallowed them.

Serious reclamation began in 1921, when the Danish state bought some 2,800 hectares of the bog's central sections and eventually held around 3,700. Canals were cut, the water was pulled out, and grass was sown for cattle on ground that had never grown anything a cow could eat. In 1935 the state put up a large farm and roughly twenty stables in the middle of it all, and by 1960 fifty-seven new smallholdings stood on land that had been open bog within living memory. The Second World War accelerated the other kind of extraction: peat was cut on a large scale for fuel, and what had been a continuous dome of moss was reduced to fragments, most of them in the western part.

Most of the area became farmland between 1920 and 1945, and out of it came the vildmose potato, a culinary speciality of northern Jutland. Several varieties are grown and sold under the name. What they share is the peat: the peels come out very thin and smooth, the flesh does not soften easily in the pot, and the flavour is distinct enough that Danes will pay a premium and argue about it. The growers' guild in Store Vildmose is a cooperative of six, and they have worked through the Vildmoseporten fund toward turning one of the old stable farms into a regional and event centre — a bog reclaimed twice, once for agriculture and once for the story of agriculture.

Around six thousand hectares carry the name today, and roughly 1,895 of them are protected, under conservation orders laid down in 1940, 1973 and 2000 and under EU habitat designation as part of the Natura 2000 network. The scientific and archaeological value is protected too, which is unusual and telling. In the surviving bogland you can find cloudberry and the carnivorous great sundew, and a breeding population of corn crake — a bird whose rasping two-note call has fallen silent across most of western Europe. Not everything held on. The marsh fritillary butterfly lived here once and has not been recorded for twenty years. Otter used to range across the bog and may yet return, along with sea lamprey; both are protected species in Denmark.

There is a regional museum in Brønderslev, the Vildmosemuseet, devoted to the cultural history of the bog — the peat cutters, the state smallholders, the potato growers, the whole century of human effort aimed at making this ground behave. Standing at the edge of the untouched sections, the argument the place makes is quieter than that. Raised bogs build themselves upward out of their own dead moss, millimetres a century, entirely on rainwater. Draining one takes a few decades. Growing one back takes considerably longer than a country's attention span, which is why the fragments here matter more than their acreage suggests.