The Curonian Spit is a 98-kilometre thread of sand that once drifted so freely it buried entire villages. Barely 400 metres wide in places, it separates the open Baltic from a shallow lagoon and carries the highest moving dunes in Europe: 35 metres on average, the tallest close to 60. The danger was man-made. Forest was felled here through the 1700s for ships and fuel, and the loosened sand began walking eastward at up to 15 metres a year. Around fourteen settlements went under between the 16th and 19th centuries, and the graveyards of Karvaičiai and Nagliai lie somewhere beneath the Dead Dunes still.
From 1825 the Prussian administration fought back with marram grass, pine seedlings and a long artificial ridge raised along the seashore to catch the sand before it moved inland. That two-century campaign is why UNESCO listed the spit in 2000 as a cultural landscape rather than a wilderness: almost everything green on it was planted by hand. The Lithuanian half, 52 kilometres of it, is a national park where the sand itself is off-limits, because one person sliding down a slope shifts tons of it. You climb the Parnidis Dune above Nida on a wooden stairway instead. At the top stands a granite sundial column, raised in 1995, broken by a hurricane in 1999 and rebuilt in 2011. From beside it the place explains itself: Baltic surf on one side, the pale shallows of the lagoon on the other, red-and-blue fishermen's houses below, grey lichen-crusted dunes running north. Twice a year the air fills as well, as between 10 and 20 million birds funnel along the strip in spring and autumn.