"The Prussian Palaces and Gardens Foundation Berlin-Brandenburg (German: Stiftung Preußische Schlösser und Gärten Berlin-Brandenburg; SPSG) was founded by a treaty of 23 August 1994 between the German federal states of Berlin and Brandenburg as a public foundation following German reunification. The treaty came into force on 1 January 1995.The foundation is separate from the considerably larger Prussian Cultural Heritage Foundation (Stiftung Preußischer Kulturbesitz)." - (en.wikipedia.org 30.01.2020)
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