Actually, the answer is art. Allow us to explain.
Just don't ask us to explain the art.
Squatter communities usually involve a bunch of weirdos who spend most of their time making art living rent-free outside the confines of society's laws. There's one in Copenhagen, Denmark, that's been there for almost 45 years, containing about a thousand squatters/artists. There are independent squatter communities in the United States, too -- we visited Slab City, California, last year -- but they tend to exist well off the beaten path. That's because, well, what they're doing is usually illegal as hell. "Squatting" by definition means they didn't pay for the land they're sitting on, and in almost every case lots of people are unhappy about it.
The two anarchist-ish squatter compounds we visited were both in Ljubljana, the capital of Slovenia. The first, Metelkova, has been around for more than 20 years and hosts a shitload of art from renowned painters, sculptors, etc., from around the world:
This used to be a Yugoslavian army guard tower.
And this used to be a literal nightmare.