This memorial (with a small museum) commemorates the Battle of Sutjeska (Bitka na Sutjesci). This was codenamed Fall Schwarz by the Germans. The battle lasted from May 15 to June 16, 1943 and aimed to destroy Josib Broz Tito's Partisan army.
The Germans deployed 127,000 soldiers from Germany, Italy, Bulgaria, the NDH and Greek SS, along with 300 aircraft. The Partisans had 18,000 men.
After heavy fighting, the Partisans managed to break out of the encirclement with the majority of the men. All those left behind, including an entire hospital, were murdered by the Axis armies. A total of 6391 Partisans and 2000 civilians were killed.
Since most of the Partisans were able to escape together with Josib Broz Tito, the Fall Schwarz operation had failed. This battle is therefore seen as the turning point of the battle in Yugoslavia in World War II. (Source: Tracesofwar.nl)