Oranienburg is located 35 km north of the centre of Berlin. It was first mentioned in documents in 1216. Margrave Albert the Bear ordered the construction of the castle on the banks of the Havel River. Around the castle grew a settlement of traders and craftsmen. In 1646, Friedrich Wilhelm I of Brandenburg married Louise Hen riette of Orange-Nassau. She loved the town so much that Wilhelm gifted the entire region to her. A new castle was built and renamed Oranienburg.  Oranienburg was the site of one of the earliest Nazi concentration camps. Located on the outskirts of the town, 200 000 people were interned there over the nine years of operation. About 20 000 people died there. It was liberated by the Soviet Red Army in 1945. The Soviets reopened the site as Soviet Special Camp 7. About 12 000 people, mostly Nazis not awaiting trail, died here before the camp was closed in 1950. The remains of the 12 000 people were discovered in the 1990s.  Oranienburg was also the centre of ...