Small icebergs bob on the waves. The beach is gray and frozen. To the north are the Dead Dunes, and to the south – past the Valley of Death – is the forested peninsula that marks the Russian border. Squeezed between a freshwater lagoon and the roaring Baltic Sea, the shifting Sand beneath my feet has swallowed villages, occasionally spitting out bones from abandoned cemeteries. It is, perhaps, an unlikely destination for a winter holiday.

But everything about Lithuania’s Curonian Spit is unlikely, and this is the secret of its stark, unreal beauty. A 61-mile-long sandbar that arcs alongside the Baltic coast, half in Lithuania and half in the Russian exclave of Kaliningrad, its unique ecology has earned it Unesco world heritage site status. A landmass formed from enormous dunes that rose from the sea 5,000 years ago – legend says they were created by a giantess called Neringa – the spit became densely forested with birch, oak and pine.

Over the centuries it was settled by pagan Balts who traded in the amber on its coast – the start of the ancient Amber Route that stretched to the Mediterranean – and then by crusading Teutonic Knights, Prussians, Lithuanians and Russians. Today there are elk and boar in its forests, miles of unspoiled white sand beaches, and the fossilised resin of millions-of-years-old pines can still be found along its shore, translucent pebbles that glow like honey when the light shines through. Most visitors come in summer but we arrive in January, drawn by the thought of winter skies, snow-covered sand and silence.

The journey is possible by public transport, but we hire a car in Vilnius and drive for three and a half hours to reach the port of Klaipeda, where a clanking vehicle ferry transports us across the northern end of the Curonian Lagoon. From there, the spit’s only road leads south through dense forest into the Curonian Spit national park. At the village of Juodkrante we stop to climb the Hill of Witches, once a pagan pilgrimage site and now covered with wooden statues depicting the giantess Neringa and other figures from Lithuanian folklore. Appropriately for Europe’s last pagan country, converted to Christianity only in the 15th century, there’s a distinctively animist flavor to the folk culture here. It only seems natural that the land should be alive.

It is: in the 18th century, people started felling the forests that had kept the dunes in place, and mountains of sand began migrating. Despite efforts to hold them back they engulfed entire villages, burying 14 settlements over the next hundred years. The rampaging dunes were only halted when a German astronomer called Johann Daniel Titius proposed the building of a 60-mile-long sand ridge, along with a dedicated reforestation campaign.

Ice clunks against the shore, the wind whistles in the pines, and there is an atmosphere of deep hibernation

This early ecological restoration project worked only too well: now the dunes have been tamed, to the extent that their continued existence is under threat. Visitors are warned that a single footstep can displace tons of sand, and the giant Parnidis Dune, the spit’s most iconic feature, has lost 10 meters of its height in the past three decades. Boardwalks protect the most popular dunes from traipsing human feet, and there are “strict reserves” where people cannot enter. Throughout our stay I am struck by the delicate balance between humans and nature, on this slender thread of sand between salt and fresh water.

We make our base in the village of Nida, near the border with the Russian exclave. Modern apartments lie inland but the seafront is lined with wooden fishermen’s cottages painted oxide red, with carved gables jutting up like the dragons on Viking longboats. Once an artist colony – Thomas Mann had a summer house here, and Jean-Paul Sartre and Simone de Beauvoir were prominent visitors – it transforms into a holiday resort in warmer months, when thousands of Polish and German tourists come to swim and sunbathe.

In winter it’s practically deserted, but that suits us fine. Ice clunks against the shore, the wind whistles in the pines, and there is an atmosphere of deep hibernation. In a coastal meadow called the Valley of Silence we take a seat on Neringa’s Chair—an artist’s installation carved from giant blocks of wood—to watch the ice in the lagoon and listen to the sound of nothing.

The following day we climb the steps to the summit of Parnidis, 52 meters high and still a “drifting dune” that moves between 0.5 and 10 meters a year. Topped by the imposing obelisk of a granite sundial carved with runes, a monument to Baltic mythology, it affords a sweeping view over sand, sea and sky. From here, a marked walking trail leads on a three-hour loop along the edge of the frozen desert – we catch a glimpse of a sea otter on the icy shore below – through the ominously named Valley of Death and along the boundary of the Grobstas Strict nature reserve, which forms a protected no man’s land between Lithuanian and Russian territory.

Then a path through pine forest takes us to the Baltic Sea, an abstract painting of slate grey, deep blue and flecks of white. We strike amber on this beach, filling our pockets with prehistoric resin that ranges in color from the palest honey to opal and magma red, and return to the guesthouse with the sea still roaring in our ears. Amber washes up on these beaches ever winter.

Half a dozen villages lie buried somewhere under our feet, commemorated by an installation of six stark wooden crosses

A short drive to the north is another reserve called the Dead Dunes, a further testament to the awesome power of sand. Accessible via a series of boardwalks – signs warn against stepping elsewhere to protect the delicate ecology – this is the most eerily beautiful place we’ve seen so far. Half a dozen villages lie buried somewhere under our feet, commemorated by an installation of six stark wooden crosses. The prints of foxes, deer and birds stipple the sand in all directions, a reminder that this seemingly desert is a haven for wildlife, and far away are the dark bulks of elk grazing on the beachgrass.

I end the day with something I’ve been steeling myself for all week: a breathless plunge into the lagoon, wading through the slush-ice. Ten seconds is all I can take, and when I emerge my hands and feet have turned an alarming shade of purple. Luckily, Lithuanian cuisine is the very definition of restorative: cheese soup, potato pancakes, dumplings in every shape and size, cabbage-wrapped pork, salted herring, and the amazing gyrbu sriuba, which is wild mushroom soup served in a bowl made of rye bread. The only green vegetable we see during our stay is a gherkin, but you don’t come to the Baltic coast for greenery in winter.

If you come for anything it’s for sea, snow, sand and silence. After immersion in all these things, the roar of traffic on the mainland in the industrial port of Klaipėda comes as a shock. But on our drive back to the ferry, we had a last sighting of two elk – much closer than the ones before – lolloping between the trees that anchor the drifting dunes in place. The vision stays with me for a long time. Days later, I find flakes of amber in my pocket.

The bus from Vilnius to Nida costs around €20, or cars can be hired from Vilnius train station (we used TopRent). The car ferry from Klaipeda to the Curonian Spit costs €16 return. Accommodation in Apartamentai Niden from €58 per night