The Battle of Ortona (December 20, 1943 to December 27, 1943) was a small yet extremely fierce battle fought between German Fallschirmjäger (paratroops), and assaulting Canadians forces from the 1st Canadian Division.

Taking place in the small Adriatic Sea town of Ortona, with its tiny peacetime population of 10.000, the battle was the site of what were perhaps the deadliest close quarter combat engagements of the entire war. Some dub this the "Western Stalingrad"

Ortona was a town of strategic importance due to its deep-sea port. It was also well surrounded by cliffs on the east and north, and deep ravine on the west. This made Ortona almost impregnable, the only option for an assault would be from the south, which offered the only entrance point. Ortona also constituted part of the "Winter Line", and the Germans were ordered to "fight for every last house and tree".

The Canadians faced a unit from the German 1st Parachute Division. These soldiers were battle-hardened after years of war, and were ordered by Hitler to defend Ortona at any cost. The Germans had placed various barricades and left rubble strewn throughout the narrow sidestreets surrounding the Piazza Municipale. The only available route for the Canadian tanks was through the Corso Vittorio, which was booby trapped; traps would serve the Germans with deadly efficiency during the 7 days of bitter fighting.

The Germans also concealed various machine guns and anti-tank emplacements throught the town, making virtually any street a deathtrap to the advancing Canadians. The house to house fighting was vicious and the Canadians made use of a new tactic: "mouse-holing".

This tactic involved using weapons such as the PIAT (or even cumbersome anti-tank guns) to breach the walls of a building. The soldiers would then throw in grenades and assault through the mouseholes, clearing the ground floors and making their way up, where both adversaries struggled in brutal close quarters combat. Mouseholing was also used to pierce through walls into adjoining rooms, sometimes catching enemy troops by surprise. The tactic would be used repeatedly as assaulting through the streets meant certain death for the Canadian troops. Later, in a praticularly deadly incident, a German demolished an entire house packed with Canadian soldiers; only one soldier survived. The Canadians repeated the act to the Germans, killing 2 platoons; such was the nature of the fighting in Ortona.

After 8 days of fighting, the attrited German troops who lacked reinforcements finally surrendered the town and retreated. The Canadians lost 1374 casualties, almost 25% of all Canadian casualties in the Mediterranean theatre.