Berlin has a lot of real-estate with unclear ownership, due to seizure of property during the nazi time and communism, sometimes multiple times. Add a few level

Berlin has a lot of real-estate with unclear ownership, due to seizure of property during the nazi time and communism, sometimes multiple times. Add a few levels of inheritance and you get real estate that is unusable because it belongs to a lot of people at once, all in a decade long court battle with each other.