The first mass liquidation of prisoners in Donja Gradina, on the right bank of the River Sava, took place in January 1942. It was carried out on the orders of Stanko Staniša Vasilj, Ustasha lieutenant with the First Ustasha Combat Defence Unit of Jasenovac. Since the winter was harsh, it was impossible to dig graves, so the Ustasha transported the villagers of Jablanac by ferry to Donja Gradina, killed them and then burned their bodies in the houses of the evicted villagers of Donja Gradina.
This wide, marshy area, subject to flooding, was inaccessible, far from communication routes, and guarded by a series of bunkers.
The ferry formed a constant means of connection between Donja Gradina and Camp III (Brickworks) in Jasenovac and was used to transport prisoners across the river to Gradina.
From early 1942 onwards, up to the very last day of the existence of Camp III (Brickworks), mass liquidations of prisoners took place in Donja Gradina. Nine burial sites containing 105 mass graves, covering a total area of 10,130 m² have been found. A further 22 mass graves, the extent of which has not yet been confirmed, have also been found.
At the mouth of the River Una, where it joins the River Sava, there used to be a tree known as the “Poplar of Sighs”, or “Brother Satan’s Poplar”, as the prisoners called it, a natural feature bearing witness to the horrors of the Ustasha crimes.
Hangings took place from the branches of the poplar, during which the victims were tortured in the cruellest manner. Ustasha colonel Miroslav Filipović Majstorović, called “Brother Satan” by the prisoners, excelled at this particular form of torture.
The tree rotted from the inside and fell down in 1978. It was then preserved and protected and fixed by means of metal pins to a metal plate, in a horizontal position.
The Act on Building and Financing the Memorial Site of Donja Gradina (OG Socialist Republic of Bosnia and Herzegovina, no. 13/75) declared Donja Gradina to be a memorial site and preparations began for re-ordering it. An association agreement on the founding, maintenance, use, construction and management of Jasenovac Memorial Site drawn up in 1983 included Donja Gradina in Jasenovac Memorial Site.
A large number of mass graves, the terrible evidence of Ustasha genocidal policies, stretch in groups or individually across the wide fields next to the River Sava. Almost eleven kilometres of paths lead the visitor through the largest execution site of the Jasenovac camp system, where nine burial fields are marked with signs bearing details of the size, number of mass graves, and surface area of each field. Excerpts from works of poetry and prose complete the impression.
The woods, meadows, clearings and solitary trees of the flat ground create a special atmosphere of complete peace, which allows visitors to experience the full weight of events, by contrasting the idyll of nature with the terrible crimes which the Ustashas committed here.
When the Socialist Federal Republic of Yugoslavia broke up in 1991, Jasenovac Memorial Site was divided into two geographic and administrative units; Jasenovac Memorial Site in the Republic of Croatia and Donja Gradina Memorial Site in Bosnia and Herzegovina.