On January 12, 1945, the Red Army launched the massive Vistula–Oder Offensive into German-occupied Poland, which saw the Soviet forces and their Polish allies advance 483 km from the Vistula to the Oder, only seventy kilometers from Berlin, in a little over two weeks.
Since the invasion of Poland by Nazi Germany and the Soviet Union in September 1939, the country had been divided among the two powers under the terms dictated by the Molotov–Ribbentrop Pact. But after the German invasion of the Soviet Union in the summer of 1941, the entirety of Poland fell under German rule, and the Nazis proceeded to advance their genocidal policies across the country.
The Eastern Front
Meanwhile, the Wehrmacht continued its advance eastwards. By December 1941, after months of fierce battles in increasingly harsh weather, the German army and their allies had almost reached the outer suburbs of Moscow, one of the primary military and political objectives for Axis forces in their invasion of the Soviet Union, where the exhausted troops were forced to suspend their offensive.
But despite large territorial gains made by Axis forces, Moscow and Leningrad remained in Soviet hands and the Red Army retained a considerable part of its military potential. Reinforced by freshly mobilised reserves, the Soviets were able to launch a counter-offensive all along the front throughout the winter, which forced the German armies back and removed the immediate German threat to the Soviet capital.
Stalingrad
Although plans were made to re-attack Moscow, the front re-opened the following summer in a different direction with the Germans launching a major offensive against southern Russia to seize the oil fields of the Caucasus and occupy the Kuban steppe, while maintaining positions on the northern and central areas of the front. With the German armies following the Don river south, the Soviets decided to make their stand on the Volga, at Stalingrad.
By February 1943, after five months, one week and three days of fierce close-quarters combat and direct assaults on civilians in air raids, the Axis forces in Stalingrad, having exhausted their ammunition and food, surrendered. The following summer, the Red Army launched a series of successful counter-offensives which gave the Soviet Union the initiative and marked the end of German superiority on the Eastern Front.
After expelling German forces from the Leningrad region, thereby ending the most lethal siege in history, 872 days after it began, the Soviet forces started pushing westwards. By June 1944, when the Western Allies launched Operation Overlord and invaded northern France, the Soviets had liberated Crimea, largely expelled Axis forces from Ukraine, and made incursions into Romania.
The Warsaw Uprising
The Soviets then launched Operation Bagration into Belarus before forcing German troops from Eastern Poland, where they formed the Polish Committee of National Liberation, established in opposition to the London-based Polish government-in-exile, which was recognized by the Western allies, to exercise control over Polish territory retaken by the Red Army and the newly reorganized Polish People’s Army.
In the wake of the successful Operation Bagration, the Red Army and their Polish allies managed to secure three bridgeheads west of the Vistula river where they started building up large amounts of materiel and manpower for the next offensive: more than 2 million men and 4,000 tanks were divided into two fronts commanded by Marshal Ivan Konev, occupying a bridgehead near Sandomierz, and Marshal Georgy Zhukov, holding the sector around Warsaw.
With the Red Army closing in on the Polish capital, the Western-backed Polish Home Army, hoping to liberate the city before the Soviet-backed Committee of National Liberation could assume control, launched an uprising to free the Polish capital from German occupation. But the advancing Soviet forces temporarily halted combat operations, enabling the Germans to regroup and send in reinforcements, which led to allegations that Stalin tactically halted his forces to let the uprising fail and allow the pro-Soviet Polish administration, rather than the Polish government-in-exile, to gain control of Poland.
The Vistula–Oder Offensive
Outnumbering the German forces five to one, the Red Army eventually launched the massive Vistula–Oder Offensive across the Vistula river in January 1945. After four days the Red Army broke out from the bridgeheads and started moving thirty to forty kilometres a day into German-held territory, capturing Warsaw on January 17, Kraków on January 19, encircling Poznań by January 25, and drawing up a line seventy kilometers east of Berlin along the Oder river.
In an effort to hide evidence of the Holocaust, the SS closed down the concentration camps in Poland and began forcing the thousands of remaining prisoners on death marches westward, away from the advancing Red Army. But on January 27, despite attempts by retreating SS units to destroy parts of the camp, troops from Konev’s First Ukrainian Front liberated Auschwitz and found graphic evidence of the Holocaust. The Soviets would also liberate camps such as Płaszów, Stutthof, and Ravensbrück
On January 31, the Vistula–Oder Offensive was voluntarily halted, though Berlin was undefended and only approximately sixty kilometres away from the Soviet bridgeheads across the Oder river. In a little over two weeks, the Red Army and its Polish allies had advanced hundreds of kilometers, taking much of Poland, striking deep within the pre-war borders of the Reich and breaking much of Germany’s remaining capacity for military resistance.
Aftermath
But the stubborn resistance of German forces in Silesia and Pomerania, meant that the final offensive towards Berlin was delayed by two months, by which time the Wehrmacht had once again built up a substantial force. The Vistula–Oder Offensive was followed by a period of several weeks of mopping-up, and in April, the Red Army jumped off from lines on the Oder and Neisse rivers, marking the start of the Battle of Berlin, which proved to be the culminating offensive of the war on the Eastern Front.
Characterised by unprecedented ferocity, wholesale destruction, mass deportations, and immense loss of life due to combat, starvation, exposure, disease, and massacres, the battles on the Eastern Front of the Second World War constituted the largest military confrontation in history.
Find out more about Central European history in our On this Day series.
Kafkadesk 
Good read, but your paragraph on Moscow says 1942 instead of 1941. Typo.
Pingback: On this Day, in 1946: Winston Churchill delivered his famous "Iron Curtain" speech - Kafkadesk
Pingback: Super Slovaks: Alexander Dubček and "socialism with a human face" - Kafkadesk
Pingback: On this Day, in 1944: the Polish Committee of National Liberation was proclaimed - Kafkadesk
Pingback: Who were Poland’s “Cursed Soldiers”? - Kafkadesk