It is a fortification structure built on a circular plan between 1825 and 1831. Originally it was situated on a small island surrounded with swamps, 500 m from fortress walls, at the site of an 18th century earthwork, which protected Zamość from the south. External diameter of the circular plan on which the Rotunda was built is 54 m and the diameter of the internal yard is 34 m. The height of external walls of the building is 10 m. The yard was surrounded with 20 cells with embrasures and arcades. The structure was connected to the town by means of a road and the road was protected by embankments and a moat. After the fortress was liquidated in 1866 the internal arcades were walled up and the building was converted into a weapons and ammunition storehouse. It performed this function till 1939.
During WW II Nazis used the Rotunda as a place of mass murder. In 1939 single executions were carried out but from 1940 several dozen people were murdered every day. The murders were connected with the fact that Nazis set up a transition camp and started to implement a plan code-named “A-B”, whose main aim was to murder members of Polish intellectuals. In November 1942 mass executions started in connection with deportation operation carried out in Zamość Region. From that time several dozen prisoners were kept in the Rotunda in inhumane conditions every day. After a few days they were either murdered or transported to other Nazi camps. At first the bodies of the victims were buried around the Rotunda. Towards the end of the war, in order to cover up traces of genocide the corpses buried earlier were dug out and burnt at the stake in the center of Rotunda yard. It is estimated that from 1940 about 40 thousand people were kept prisoner in the building; 8 thousand of them were murdered.
On both sides of the road leading to the Rotunda victims of the war are buried; their bodies have been brought here from tombs scattered all over Zamość Region. In the graves located on the right (western) side of the road Polish soldiers killed during the September campaign and partisans from Zamość Region are buried and in the graves on the left (eastern) side of the road – Soviet soldiers, Jews and victims of Stalin’s terror. The building is surrounded with a cemetery of the camp’s victims. In all, there are remains of 45 482 people in the Rotunda.
The gate which leads to the yard has the original doors with an inscription in German which reads: TRANSITION PRISONER-OF-WAR CAMP OF SECURITY POLICE. Right behind the gate, on the ruins of a cell bombed during the first days of September 1939 prisoners were shot. This tragic event is commemorated with a plaque. In the centre of the yard there is a tablet with an inscription which reads: Here Nazi criminals burnt the bodies of the victims they had murdered, prisoners of the Rotunda. May they rest in peace.
Rotunda cells are available to visitors and remind them about the fight and tragic fate of Polish people during the Second World War. The particular cells are dedicated to the victims of death camps, partisans of Zamość Region, members of different vocational groups, scouts, Siberian deportees and victims of Ukrainian nationalists. The last five cells house an exhibition of photographs and documents connected with the time before WW II and with Nazi occupation of Zamość Region, including deportations, the fate of the Children of Zamość Region and the Nazi camp in the Rotunda.
On the exterior wall of the building there are 175 tablets which commemorate the war victims of Zamość Region.
The landmark is included in audio guides