There is a concept of a building real estate in Polish legislation. It concerns a certain legal status (or a legal title to the land), namely the right of perpetual usufruct - this right is limited in time and does not find its counterpart in the legislation of the "old Union states". The right of perpetual usufruct applies only to land which is the property of local government units or the State Treasury in Poland. More at:
http://www.mflegal.pl/real_estate_in_poland_building_real_estate.html
