Anywhere so called social hot-spots exist. Mostly concentrated around social/public housing projects, where people of different ethnicity/with migrantic background concentrate and organized (drug) criminality flourishes.

The No-Go zones, expanding and overwhelming law enforcement.

Some place(s) in Sweden come to mind, where they even have an App to rate the loudness of explosions, caused by turf wars of competing groups.

The https://en.wikipedia.org/wiki/Banlieue in France.

There seem to be some similar places in Belgium, and at least one in the Netherlands.

About any https://en.wikipedia.org/wiki/Satellite_city / https://en.wikipedia.org/wiki/Commuter_town with large high-rise https://en.wikipedia.org/wiki/Housing_estate in Germany.

Do I need to say anything about recent events in some downtowns in the USA?