The Heiligenbeil Pocket or Heiligenbeil Cauldron (German: Kessel von Heiligenbeil) was the site of a major encirclement battle on the Eastern Front during the closing weeks of World War II, in which the Wehrmacht's 4th Army was almost entirely destroyed during the Soviet Braunsberg Offensive Operation (1322 March 1945). The pocket was located near Heiligenbeil in East Prussia in eastern Germany (now Mamonovo, Kaliningrad Oblast), and the battle, part of a broader Soviet offensive into the region of East Prussia, lasted from 26 January until 29 March 1945.

The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after 1922, the Union of Soviet Socialist Republics. The army was established in January 1918. The Bolsheviks raised an army to oppose the military confederations (especially the various groups collectively known as the White Army) of their adversaries during the Russian Civil War. Starting in February 1946, the Red Army, along with the Soviet Navy, embodied the main component of the Soviet Armed Forces; taking the official name of "Soviet Army", until its dissolution in 1991.

The Red Army provided the largest land force in the Allied victory in the European theatre of World War II, and its invasion of Manchuria assisted the unconditional surrender of Imperial Japan. During operations on the Eastern Front, it accounted for 75–80% of casualties the Wehrmacht and Waffen-SS suffered during the war and ultimately captured the Nazi German capital, Berlin.