September 1, 1939, the day Hitler's army invaded Poland, is one of the most infamous dates of the 20th century. But how many of us recall September 17, 1939, when Soviet forces charged into Poland from the west? Germany and Russia, acting together on terms laid out in a secret pact, tried to destroy an entire country - and nearly succeeded. The sinister partnership would not last. Two years later, Hitler turned on Stalin and invaded the Soviet Union, which would spell doom for the Wehrmacht. In the West, we think of the heroics of D-Day, but it was the Soviet Army that ultimately broke the Nazi war machine; the British and Americans merely finished it off. Stalin ends up in the history books as a saviour, along with Churchill and Roosevelt, in the struggle against Hitler. Even now, it is far easier to think of Stalin as an opponent of Hitler than as a partner. We like to tell ourselves that the virtuous side won the war, but what happened in the east confounds such notions. Even before a shot was fired, Stalin had the blood of a nearly four million Soviet citizens on his hands. Between them, the Soviets and Germans killed nearly 200,000 Poles - targeting doctors, lawyers, scientists, professors, and religious figures. They all died in a region that the historian Timothy Snyder, in his striking and important new book, calls the "bloodlands".
It was a place of shifting allegiances, an ethnic and linguistic patchwork. The zone extended east from central Poland into western Russia, and from the Baltic States in the north to the Black Sea in the south. It was a place where German, Slavic, Baltic and Jewish cultures collided and mingled.
This was the terrain of Europe's killing fields, "where the power and malice of the Nazi and Soviet regimes overlapped and interacted". Here is where the Holocaust unfolded with a grim relentlessness. The scale of battles - at Kursk, for example, where some 7,000 German and Soviet tanks clashed - dwarfed any of those fought on the Western front. The death toll, civilian and military, exceeded 20 million. Some of the regions of the bloodlands were doubly or triply occupied. It was a theatre of immense, pervasive suffering, which almost defies comprehension.