The Kvarken Archipelago (Merenkurkun saaristo) High Coast of Sweden, it has been named a UNESCO World Heritage Site.
Once weighed down by immensely heavy glaciers that melted after the end of the Ice Age, the Kvarken area is undergoing extremely fast uplift (by geological standards), with land rising about 8 mm per year — enough to create 1 square kilometer of new land every year.
The archipelago consists of some 6,550 islands. The largest of them, Replot (Raippaluoto), is Finland's 8th largest and houses the vast majority of the islands' population of some 2,500 people, but it's (just) outside the official World Heritage Site area.
Flora and fauna
The best place to start your visit is the Terranova - Kvarken Visitor Centre , located not in the archipelago, but in the nearby town of Vaasa. A few of the islands near the coast are accessible by car, but for most, you'll need your own boat.
There are four designated nature trails for hiking among the islands of the archipelago. Canoes and kayaks can be rented at some of the nature stations, and are an excellent way of getting around.
There are five "Nature Stations"  throughout the archipelago that offer basic accommodations. They're intended primarily for groups, and reservations are essential.
Camping is allowed throughout the archipelago, but open fires are only allowed at designated spots.