Why? Drugs of course.
Unofficial Flag Art of Christiania
Established in 1971 in an area formerly occupied by an army base Christiania is a self proclaimed autonomous neighbourhood covering 34 hectares of land and containing about 850 official residents.
The legal status of the area is to this day dubious. The supervision of the community has been transferred from the town of Copenhagen to the country of Denmark. A normalization of the area and a clear rule of law have never been achieved.
The whole area is basically a large social experiments that would drive anthropologist to foam from their mouths if they were told that they got a license for social studies in the community.
Christiania Breakfast Foods
The community of Christiana is made up by entrepreneurs who trade in soft drugs like cannabis, ex-hard drug users and everyone who does not agree with the normal runnings of society. This has helped to spread free thinking people, popular theater groups, yoga classes and meditation circles.
Sometimes the police try to crack down on it, sometimes they do not. It mostly depends whether Christiania is currently seen as a nuisance or a major tourist attraction.