School was out — at least temporarily — for hundreds of Vienna school children after one of them brought a hand-grenade to class. But it turned out to be a dummy.

Police spokesman Patrick Maierhofer says a lower and middle school were temporarily evacuated Monday after a 14-year old boy pulled out the grenade from his school bag.

Once at the scene, police and firefighters quickly established that the ordnance was not live and was meant for demonstration purposes. Police say the boy, an immigrant from Romania, found it there years ago and brought it to school to show it off because his history class was focusing on World War II.

About 700 school children were moved to a neighboring school before returning to their own classes several hours later.