Christmas Truce, (December 24–25, 1914), an unofficial and impromptu cease-fire that occurred along the Western Front during World War I. The pause in fighting was not universally observed, nor had it been sanctioned by commanders on either side, but, along some two-thirds of the 30-mile (48-km) front controlled by the British Expeditionary Force, the guns fell silent for a short time.

Source: Britannica