I had no idea Freetown Christiania is considered a micronation. I thought they were just hippies living in their own little part of Copenhagen.
Micronations are places that someone has declared it’s own country or at least independent. Sealand is the best known one, while Christiania is usually considered the most legit one because Denmark allowed them to slag on a lot of rules about drugs and building sites, though lately the Danish state have forced them to be less liberal about drugs whish lead to a lot of conflicts. [link]