The Russians left many of their dead lay where they had fallen during WW2. There are groups of people there that search for their remains.
When the invading German forces approached a city, it was not unusual for the Russians to create, on the spot, a new military unit that consisted of untrained men between 16 and 60 that that city who were forcibly conscripted into becoming cannon fodder for German machine guns.
There is one such story in a village on the outskirts of Rostov. The Germans grimly did their job as wave after wave of Russian men walked into their machine gun sights. The layers of bodies were four deep as wave after wave crawled over their dead countrymen headed for the German lines. Those that turned back, of course, were murdered by the local commissars who had their own machine guns.
Even the hardened German soldier was brought to tears as they realized how senseless the slaughter was.