Allegedly a "freetown" in the middle of Copenhagen it has changed quite a lot over the years. It was an abandoned army base that got occupied by squatters in the '70s as a protest against and solution to the housing situation in Copenhagen (lots of slumlords, no playgrounds for kids, lots of empty lots that were kept empty as "investments" waiting for the surrounding area to get developed, very very bad quality of homes). They managed to establish themselves and even got a promise that they were allowed to keep the area. The semi-legal status of Christiania + the fact that they wanted to keep out cops, led to the establishment of an open-air drug market. The people in Christiania realised that the sale of hard drugs wasn't really good, so they banned it, resulting in one of the only junk-free weed markets. The market was manned by people living in Christiania, which was crucial, because Christiania was also against organized crime. This meant that we had one of the only markets in the world with no hard drugs and also no (direct involvment) of organized crime. <- The police managed to fuck this up, yay!
Due to the nature of Christiania it quickly became a place where "outsiders" could hang out and feel safe, people that were not mentally well, alcoholics, the homeless and so on. This also made Christiania a perfect spot for outreach programs. It also made Christiania a cultural powerhouse with so many fantastic venues and organizations doing all sorts of cool shit. It was also a very cool example of what is possible for squatters, how much "real estate investments" suck, how direct democracy can function and a bunch of other stuff.

In the 00's the government reneged on its' promise and decided to "clear out" Christiania, like it had already done to several parts of Copenhagen - most infamously the "total sanation" of Nørrebro. Part of this "clearing out" involved a massive raid on Christianias market, where they arrested all the dealers. This would of course shut down the market, right? Like if you had a market with a bunch of sellers, who were all chill locals, and then you remove them, then their suppliers will just throw their hands in the air and say "oh well", right? Oh whoops you had the exact same thought as the Copenhagen Police, congratulations there is now an established and direct organised crime presence in Christiania, who could have seen this coming? Hope it won't bite us in the ass.
Years later Christiania was allowed to buy the land it was located on, making it "legally" owned by the citizens now. I don't know if this is directly correlated, but after this purchase is also when you can really see the gentrification of the area kick into high gear.

Over the years Christiania changed in a lot of ways. It became closed off, if you wanted to move in, you had to be approved. Most housing in Christiania now goes to the children of the people living in Christiania. Most people living in Christiania are well off. They have now shut down the open-air market and begun cooperating with police. This was done due to several violent episodes related to the weed-trade, so it's understandable. What's not understandable is the general attitude of the christianites. They say and do nothing as police go beyond shutting down the weed market, and instead harass the people that have always been in the area, harass people making use of outreach programs, harass the venues and cultural organizations that have always been part of the area. They want to replace the market with a "regular shopping street for kids". They want yet another "large city shopping street".

There have been attempts at occupying other areas near Christiania, they have all been shut down. The pretense for the raids that shut down the areas were large amounts of noise complaints. Can you guess who made those complaints? The people of Christiania! They're hypocrites and they've got a good deal that they don't want to acknowledge or share.

very reductive summary: drug market in Copenhagen, recently torn down