Maxmo
In July 2006 Kvarken Archipelago was added as an extension to the UNESCO World Heritage site of The High Coast . The archipelago is unique in that it features ridged washboard moraines known as De Geer moraines , formed by the melting of the continental ice sheet 10 , 000 to 24 , 000 years ago . 
<triplet> The High Coast <subj> UNESCO World Heritage site <obj> instance of