ARCTIC Post Offices - Santa Claus Post Office (Finland)

A very nice WWF cover from Finland, depicting a complete set issued in 2016 with three stamps with endangered species: the lesser white-fronted goose, a species of damselfly and the saimaa ringed seal. What makes this cover so special is that it was posted and cancelled at Santa Claus Post Office in Arctic Cercle (finish postal code 96930).
https://www.santaclausvillage.info/santa-claus/santa-claus-main-post-office/