Among the many fortresses scattered across the slopes of Papuk, the old town Sirač is one of the most significant fortresses. The old town Sirač is a medieval Turkish fortress with an altitude type from the 14th century at a notable position – a gulch in the center of the settlement Sirač at the exit of the river Bijela from the massif Papuk.

The fortress is situated on the right side of the river Bijela on an altitude of 200 meters. It is believed that the Old town Sirač was built by Temolars, knights from the time of Pope Kelment V in 1309. In 1763, after many years of Turkish rule in this area, Antun Janković became the owner. He bought the property for 40 000 forints. The main north wall which is 4 meters high, 2 meters wide and 14 meters long, is partly conserved, while other architecture can bee seen sporadically at the surface of the locality. The gulch is rugged by newly found caves which indicates possible founding from Paleo/Neolithic.

Geothermal springs were located at the foot of the fortress, but they were buried in the middle of the 20th century, during the World War 2. Some blocks which consolidated the old town were demolished during later building of the houses. Today’s remains are defensive walls that bear witness to the turbulent history of the Old town Sirač and its surrounding areas.