A raised bog is a strange kind of landform: it grows upward, and it drinks only from the sky. Sphagnum moss piles its own dead beneath itself, century upon century, until the surface lifts clear of the groundwater and the whole dome depends on rainfall alone. At Lille Vildmose the peat runs up to five metres thick. The process began in the Iron Age, when the climate turned wetter and older lowland fens swelled into domes. Underneath all that moss lies older geography still - seabed from a time when the water stood higher, and low rises that were islands in the Stone Age, now buried as hills within the bog. Beyond the bog proper the reserve takes in coastal slopes and beach meadows running down toward the Kattegat. What survives here is a fragment. The heath and bog it belongs to once ran south from the Limfjord all the way to Rold Skov.

Around 1760, a modest manor called Vildmosegaard was established under Count A. G. Moltke, and with it came the drainage. Four lakes were emptied – Møllesø, Birkesø, Toftesø and Lillesø – and the bog began the slow subsidence that follows any drained peatland. Industrial cutting arrived with the Second World War, when Denmark needed fuel and the bog held two millennia of compressed plant matter under its living surface. Afterwards the market shifted from heating peat to horticultural sphagnum, and the extraction ran on until 2008. The scale of it can still be read in the ground: a 700-millimetre-gauge rail network, the largest industrial narrow-gauge system in the country, laid across the moss to carry the harvest out. Every ditch cut for that work is now a problem to be solved.

Restoring a bog means more than blocking ditches. Birch and scrub colonise drying peat fast, and something has to eat them. The first answer was cattle bred to approximate the extinct aurochs. The founding herd was a genetic patchwork - a Chianina-Heck bull, four Heck cows, one Sayaguesa-Heck cow - released under controlled conditions, with three Sayaguesa bulls added in 2009. They bred well, reaching about a hundred animals by 2015, and they did diversify the vegetation. But Danish law treated them as livestock rather than wildlife, and livestock need handling, inspection, and paperwork. Free-ranging herds do not cooperate with any of that. In 2015 the decision was made to move them elsewhere and try a species that would not be classified as farm stock.

The moose vanished from Denmark roughly 4,500 years ago. In 2007 the Wildlife Management Council approved bringing it back to Lille Vildmose, not as a nostalgia project but as a browsing machine: a moose eats willow and birch at a rate no cow can match. Five calves arrived from Sweden in the summer of 2016. Four cows and a bull followed in January 2017. Ten animals in total, turned loose in a fenced bog, and they thrived - around twenty-five of them by 2020, the first free-ranging Danish moose since the late Stone Age. Between 2019 and 2021 European bison, gone from Denmark for thousands of years, were introduced into Tofte Skov. Neither species is decorative. They are the maintenance crew for a landscape that stopped being able to maintain itself.

Two old forests sit inside the reserve - Tofte Skov and Høstemark Skov - each separately fenced and closed to casual visitors, open only on guided tours. Behind those fences live some 550 red deer and a population of wild boar, animals that have had the run of these woods for generations. Overhead, Lille Vildmose is one of only two places in Denmark where golden eagles breed; white-tailed eagles nest here too, along with cranes and enormous transiting flocks of geese. The whole complex is Natura 2000 site number 17, protected for both habitat and birds, and was designated a Ramsar wetland on 18 May 2013. In 2018 it was named to Denmark's Naturkanon, and it remains a candidate for national park status. Birkesø, one of Moltke's drained lakes, has been re-established. Lille Vildmosecentret, with its exhibitions, nature school and hostel, is where most visits begin - and where you learn that the wildest place in Denmark is one that people spent two centuries taking apart.