[1] During World War II, the former Austro-Hungarian fortress was used by the Ustaša regime as the Stara Gradiška concentration camp, a part of the Jasenovac complex, the largest extermination camp in occupied Yugoslavia.
From 1945 until the late 1980s, the prison at Stara Gradiška held political prisoners of the communist regime.
[2][3] The detention facility was shut down by the Republic of Croatia in 1990, a decision made formal in February 1991.
[4] However, from October 1991 until July 1993, the prison was again re-opened by the Krajina Serbs, who captured and detained numerous Croats in the facility during the Croatian War of Independence.
[5] As of 2007[update], the municipality planned to turn the site into a museum.