The Zeelandia fortress had been extensively restored in 1974 and served as a museum until 1980. In the 1980-ties it was used as a military command center, and after that, it remained empty and abandoned for 10 years. In 1994 the museum foundation SSM decided to re-instate the building as a museum, but first, another restoration had to take place. In 1996, the museum opened its doors to the public.