An ancient Roman theater, or odeon, has been discovered in Sisak, Croatia, during renovations of the town hall. The discovery, announced in April 2025 by Croatia's Ministry of Culture and Media, occurred during renovation work prompted by the 2020 earthquakes that significantly damaged the town hall.
The theater's orchestra was found in the basement of the town hall on Roman Street. The structure includes an apsidal design with three rows of stone blocks. The find is considered exceptionally valuable, providing insights into the size and urbanism of ancient Siscia.
Sisak, formerly known as Siscia, has a rich Roman history, serving as a military camp and later an economic and cultural hub. The theater ruins, featuring a podium, orchestra, and semi-circular stone rows, are preserved and partially visible under a glass floor in the renovated town hall. This discovery highlights Sisak's historical significance within the Roman Empire.