Opening day of the Soviet Union's Operation Bagration against the Army Group Centre.
Operation Bagration (; Russian: Операция Багратио́н, Operatsiya Bagration) was the codename for the 1944 Soviet Byelorussian Strategic Offensive Operation (Russian: Белорусская наступательная операция «Багратион», Belorusskaya nastupatelnaya Operatsiya Bagration), a military campaign fought between 22 June and 19 August 1944 in Soviet Byelorussia in the Eastern Front of World War II, just over 2 weeks after the start of Operation Overlord in the west, causing the Germans to have to fight on two major fronts at the same time. The Soviet Union destroyed 28 of 34 divisions of Army Group Centre and completely shattered the German front line. It was the biggest defeat in German military history, with around 450,000 German casualties, while 300,000 other German soldiers were cut off in the Courland Pocket.
On 22 June 1944, the Red Army attacked Army Group Centre in Byelorussia, with the objective of encircling and destroying its main component armies. By 28 June, the German 4th Army had been destroyed, along with most of the Third Panzer and Ninth Armies. The Red Army exploited the collapse of the German front line to encircle German formations in the vicinity of Minsk in the Minsk Offensive and destroy them, with Minsk liberated on 4 July. With the end of effective German resistance in Byelorussia, the Soviet offensive continued on to Lithuania, Poland and Romania over the course of July and August.
The Red Army successfully used the Soviet deep battle and maskirovka (deception) strategies for the first time to a full extent, albeit with continuing heavy losses. Operation Bagration diverted German mobile reserves to the central sectors, removing them from the Lublin–Brest and Lvov–Sandomierz areas, enabling the Soviets to undertake the Lvov–Sandomierz Offensive and Lublin–Brest Offensive. This allowed the Red Army to reach the Vistula river and Warsaw, which in turn put Soviet forces within striking distance of Berlin, conforming to the concept of Soviet deep operations—striking into the enemy's strategic depths.