This photo is titled "German tanks cross the Don". I'm not sure, the Don is wider than this river. That said, its not far off. This appears to be SW Russia near the Don bend in the summer of 1942. At that point, it looked like the German gamble to attack in the South was paying off. The idea was to smash the Red Army in the South and take the Russian oil fields in the Caucasus. Hitler had insisted on an offensive aimed at the oil supply, both because Germany was desperate for oil, and to deny it to the Russians.
By mid-August, the Wehrmacht was advancing up to 20 miles per day with the Red Army in disarray. The overall commander of the operation, von Manstein, sensed an opportunity to deal a knock-out blow to the Red Army. When the Russian defense stiffened on the West bank of the Volga, von Manstein saw his chance. He set the German 6th Army to finish the job by taking an industrial city on the Volga called Stalingrad.
Like Lee at Gettysburg, von Manstein had lost respect for his opponents and thought they would collapse if he could just hit them hard enough.
