UNESCO - Kvarken Archipelago, Finland

The full name of the WHS is High Coast/ Kvarken Archipelago, but the High Coast part belongs to Sweden; they are situated in the Gulf of Bothnia, a northern extension of the Baltic Sea. The 5,600 islands of the Kvarken Archipelago feature unusual ridged washboard moraines, ‘De Geer moraines’, formed by the melting of the continental ice sheet, 10,000 to 24,000 years ago. The Archipelago is continuously rising from the sea in a process of rapid glacio-isostatic uplift.

Many thanks to Heli for this swap on FB :)