Alta Costa / Archipiélago de Kvarken

The High Coast was inscribed on the World Heritage List in 2000, and in 2006 the property was extended with the Kvarken Archipelago, on the Finnish shore of the Gulf of Bothnia, forming a transboundary property between Sweden and Finland of some 3,369 km², of which close to 1,994 lie on the Finnish side.

Its value is geological and of exceptional clarity. During the last glaciation the ice sheet, up to three kilometres thick, pressed the Earth's crust down under its weight. As it melted, the crust began to recover its position in a process called isostatic rebound, which here has reached 285 metres of uplift since deglaciation, the highest figure documented on the planet, and which continues at almost a centimetre a year.

The result is a landscape in permanent transformation and perfectly legible. On the Swedish High Coast, former shorelines now lie high above the sea, and cliffs, raised beaches and sea caves appear inland, deep in the forest. In the Finnish Kvarken, of much lower relief, the process shows itself as an archipelago in formation, with De Geer moraines emerging and gradually joining up, bays that close off and become lakes, and a coastline that changes within a single human lifetime. It is the world's reference site for the study of isostasy.