After defeating the remnants of the German army and occupying Berlin, the Soviet Union, under the dictatorship of Josef Stalin, attempted to gain complete military and economic control of the Balkans.  Easily securing Rumania, Bulgaria and Hungary, most of whom's armies were destroyed on the Russian Steppes, the Russians turn their eyes toward Yugoslavia and Greece.  
The Yugoslavians stunned the Russians attacking east of Belgrade, routing a strong Soviet force in the battle of Pancevo.  Tenacious if anything,  the Soviets attempted an encircling movement on Belgrade,  overwhelming partisan groups at Sabac and Lozinca and defeating the main Yugoslavian Army, forcing it to split in two, leaving part of the army to defend Belgrade 
while the rest fled south to regroup.  This battle concerns rearguard action by a crack Yugoslavian division left to delay the Russian's capture of Belgrade.  One of the key (and bloodiest) battles was around hill 69, east of the city.  There a Soviet armored regiment attempted to cross the Sava and capture the hill, from where their artillery would command the city.  
Needless to say the Yugoslavians put up heavy resistance, and it was not without great cost the Soviets finally captured the hill.