World War II: The German 4th Army is almost destroyed by the Soviet Red Army.

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 4th Army (German: 4. Armee) was a field army of the Wehrmacht during World War II.