Freetown Christiania has been controversial since it was created in a squatted military area in 1971. Some call it it's own city while others call it a large commune. The residents refer to it as staden (the town), short for fristaden (the freetown). Copenhagen even regulates this area under a special law confirming its independence for now.
Needless to say, this city within a city was a thought-provoking area to visit.