Why is Finland the happiest country on earth?

Finland came out very well here due to its low crime levels. Finland also has a universal health care system which a significant factor in how happy its citizens feel. When all these factors are combined, it allows most Fins to have a high standard of living and to feel content in their daily lives.

Who are Finns descended from?

The closest genetic relatives for Finns are Estonians (FST to Helsinki 40 and to Kuusamo 90) and Swedes (FST to Helsinki 50 and to Kuusamo 100). The FST values given here are actual values multiplied by 10,000.

Why didnt the Vikings invade Finland?

The Vikings werent militarily superior to other contemporary soldiers, so they would usually avoid combat if they didnt have the upper hand, which they wouldnt without their ships. So while they did have contact with the cultures in this region, it was generally peaceful contact and consisted mainly of trade.